The actual owners’ manual that came with the car showing the differences can be seen here:

This describes and illustrates the modifications made, although not all:

  • Both the Camber and castor angle for the front and rear suspension were changed.
  • The wheels were changed to 8Jx18″ front and 10Jx18″ rear Speedline split rim wheels.
  • Tyres were changed accordingly to 225/40ZR18″ front and 265/40ZR18″ rear Pirelli P Zeros.
  • Doors were made of Kevlar and carbon to reduce weight.
  • The seats were racing style bucket seats made in kevlar and carbon, coated with red fabric.
  • There was a new design steering wheel with the cars limited edition numbers engraved on the front.
  • The front and rear bumpers were made of Kevlar and carbon, again to save a considerable amount of weight.
  • Whilst this manual does not state the GTC has drilled aluminium clutch and brake pedals they can be clearly seen on the illustrations of the interior.
Exhaust system Item No.22 Part No. 95200023 RH Exhaust Manifold - Valid for 348 Comp These exhaust manifolds are unique to the 348GTC and probably account for the rumoured extra 10bhp probably making the GTC produce 330bhp and not the 320bhp quoted for the standard F119H engine. 
Item No.23 Part No. 95200022 LH Exhaust Manifold - Valid for 348 Comp 
LHD Clutch Item No2 Part No. 157273 PEDAL slab Not for Spider So all LHD GTB/GTS/GTC cars had the drilled aluminium clutch pedal but not Spiders. 
Item No53 Part No. 14441324 Screw 
RHD Clutch Item No4 Part No. 149295 Pedal Slab And all RHD GTB/GTS/GTC including all Spiders had a rubber covered clutch pedal 
Gear knob Item No.11 Part No. 95403828 Gear Knob Valid for 348 Comp All GTC cars had the Chrome gear knob rather than the black knob of the other cars. 
Brake pedal Item No.2 Part No. 15272 Pedal Slab (Not for Spider) and at the bottom of the page (Not for GD) Again all LHD GTB/GTS/GTC cars had an aluminium brake pedal but not Spiders. 
Item No.38 Part No. 14441324 Screw 
Brake and Throttle Item No.4 Part No. 149292 Pedal Slab 
Item No 27 Part No. 138199 Accelerator Pedal 
Pedals So according to the parts manual at least, as with the clutch pedal, all LHD GTB/GTS/GTC cars had the drilled aluminium pedals for the brake and all RHD cars clutch and brake pedals were covered in rubber but all (LHD&RHD) cars had a standard black metal pedal for the accelerator.  Of the three RHD cars I personally saw when new, none of them had aluminium pedals but I guess the LHD cars did? Most RHD cars have since had drilled aluminium clutch and brake pedals fitted and some have had the throttle pedal and clutch rest changed to drilled aluminium too. Some cars have had the challenge style drilled aluminium pedals fitted. 
Steering Wheel Item No1 Part No.148991 Steering wheel The unique steering wheel is leather covered, has 348GT Competizione written at the top and then the edition number out of 50 below the horn button e.g. 1/50. 
Wheels and TyresItem No.3 Part No. 160026 Front Tyre Pirelli P Zero 220/40ZR18 These are the unique 18 Wheels and rims made by Speedline for Ferrari, fitted from new with Pirelli P Zero Tyres. 
Item No.3 Part No. 160027 Rear Tyre Pirelli P Zero 265/40ZR18 
Item No.4 Part No. 146989 Wheel Stud 
Item No.10 Part No. 149552 Front Built Up Wheel Rim 8"J x 18" 
Item No.10 Part No. 160563 Rear Built up Wheel Rim 10"J x 18" 
Kick plate and Trim Item No. 8 Part No. 64447300 RH Kick Plate Item No 8 are the door sill kick plates made of a Carbon/Kevlar composite instead of the normal black plastic ones. 
Item No. 8 Part No. 64447400 LH Kick Plate 
Item No.72 Part No. 62929200 LH Front Mark 
Item No.72 Part No. 62929100 RH Front Mark 
Item No72 are the enamelled Ferrari Scuderia Shields on the front wings 
Passenger compartment carpetsItem No. 12 Part No. 64453300 Complete Control Unit CoverThere are two of these control unit covers behind the two seats and are made of a Carbon/Kevlar composite instead of the normal material.
Front compartment carpetsItem No. 1 - Part No. 64453100 Carpet series for Front Trunk Compartment (LH Drive)Why the front trunk (boot) compartment carpet is unique for the GTC I have no idea unless it is made of a different material that weighs less?
Item No. 1 Part No. 64453200 Carpet series for Front Trunk Compartment (RH Drive)
Rear engine coverItem No. 31 Part No. 95404618 "348 GT Competizione" MarkThis is the model designation script "348 GTCompetizione" on the rear engine cover.
DoorsItem No. 15 Part No. 64404300 L.H DoorThese are the Carbon/Kevlar door and door grills.
Item No. 15 Part No. 64404200 R.H Door
Item No. 21 Part No. 62929700 L.H Door Grill
Item No. 21 Part No. 62929500 L.H Door Grill
Front bumperItem No. 1 Part No. 62975110 Front BumperThis is the Carbon/Kevlar Front Bumper
Rear bumperItem No. 1 Part No. 63975210 Rear BumperThis is the Carbon/Kevlar Rear Bumper
Glasses and gasketsItem No. 12 Part No. 62933100 Rear Window (Lexan)So, according to the parts manual at least. A GTC should have Lexan (i.e. light weight) rear left hand and right hand rear fixed window glasses as well as the actual rear window. The cars that I have seen all appear to have a heated rear screen and normal rear windows so I doubt if many or any of the GTC road cars had lexan fitted. If you know different please let me know.
Item No. 16 Part No. 62933200 L.H Rear Side Glass (Lexan)
Item No. 16 Part No. 62933300 R.H Rear Side Glass (Lexan)
SeatsItem No. 1 Part No. 62929800 Complete L.H. SeatThese are the complete Competizione seats and component parts.
Item No. 1 Part No. 64389000 Complete seat upholstery
Item No. 2 Part No. 62929600 Complete R.H. Seat
Item No. 2 Part No. 64389000 Complete seat upholstery
Item No. 3 Part No. 64388100 Seat Back Sponge
Item No. 4 Part No. 64388500 L.H. Lateral Sponge
Item No. 5 Part No. 64388200 Sitting Sponge
Item No. 6 Part No. 64388400 R.H. Lateral Sponge
Item No. 7 Part No. 64388800 R.H. Guide for L.H. Seat
Item No. 8 Part No. 64388900 L.H. Guide for L.H. Seat
Item No. 9 Part No. 64388600 R.H. Guide for R.H. Seat
Item No. 10 Part No. 64388700 L.H. Guide for R.H Seat
Item No. 11 Part No. 62532000 Sliding Control
Item No. 12 Part No. 63948300 R.H. Seat Spacer
Item No. 13 Part No. 63948200 L.H. Seat Spacer
Item No. 14 Part No. 13028734 Screw
Item No. 15 Part No. 63395300 Elastic Plate
Item No. 16 Part No. 14308921 L.H. Seat Rear Fixing Screw
Item No. 17 Part No. 14306424 R.H. Seat Rear Fixing Screw
Item No. 18 Part No. 14306334 Seat Front Fixing Screw
Item No. 19 Part No. 12601374 Washer
Item No. 20 Part No. 14496506 washer
Carpet trimsPart No. 1000678 Black Whist the carpet trim series in black is sometimes also used on a GTBThe Inner compartment carpets were unique to the GTC, probably to allow for the different seats to be fitted.
Part No. 1000778 Black (L.H. Drive)
Part No. 1000789 Black (R.H. Drive)
Foot rest slabIn addition to the above there are one or two other anomalies. For example on one car I have seen the passenger slab foot rest plate is made from Carbon/Kevlar where as most of the cars I have seen certainly in RHD form, they are metal.This foot rest slab was seen on car No8. Perhaps it was made specially and retro fitted? Anyone seen another?

The parts book shows us there are one or two extra differences the manual does not give us. It also shows us one or two differences between LH Drive and RH Drive cars such as the pedal differences. It also shows that not all the Competizione parts were fitted (certainly on some cars) like the Lexan windows.

Does anyone know of any other differences not mentioned here? As explained there are many other differences on a GTC other than on a “normal” 348 but these differences are shared with the GTB, GTS and Spider.