From the A pillar on back the Testarossa and 512TR look exactly the same to my eye. TR has a slightly more muscular front end. Although looking at the list of improvements from the Testarossa to the 512TR. The 512TR is the car most would want to drive. I suspect this has more to do with you wanting to see Testarossa badge on the back of the car, hahah. Which is cool, I can dig it !
The internal differences are substantial.
Engine- Block is still flat 12 boxer engine cast in light alloy, crankshaft still has seven main bearings, the cylinders still have four valves and each cylinder banks still has two overhead cams.
1. Bore and stroke of 82mm by 78mm, 4942 cc capacity (unchanged);
2. HP increased from 380hp SAE to 421, with most of the increase coming from a redesign of the intake manifolds, a repositioning of the injectors, and a recalibration of the injectors, and a recalibration of the engine management system, the later controlling the integrated electronic fuel injection system;
3. Torque increased from 354lb ft to 360;
4. 0-60mph, 5.7 sec to 4.8;
5. Top speed- 180mph to 192;
6. New cylinder liner manufactured in aluminum with Nikasil coating;
7. New pistons due to larger intake valves;
8. Increase in compression ratio (10.1 to1)
9. Modified cylinder head gaskets due to a higher compression ratio and a different cylinder head coolant circulation layout;
10. Reinforced camshafts of a new profile;
11. Valve tappets with a new design bucket and springs;
12. New intake valves of a larger diameter;
13. Separate air boxes with filters, with a dynamic air intake;
14. Longer and straighter air intake manifolds;
15. Integrated electronic fuel injection system and ignition (Bosch Motronic 2.7) with self-diagnostic capabilities, and with ECU located in the cockpit;
16. Double independent submergible fuel pumps;
17. Exhaust manifolds with new layout;
18. Metallic type pre-catalyst converters;
19. Exhaust muffler with resonators and new heat shields;
20. Aluminum oil radiator with U circulation and without fan, allowing for better permeability; aluminum tubing;
21. Dual copper water radiators with U circulation in series and new aluminum tubing;
22. Coolant expansion tank located between intake manifolds;
23. More powerful alternator;
24. Secondary air pump with new air distribution pattern.
Chassis- Up front, the chassis frame was strengthened around specific points; for example, the steering rack mounts and the front suspension mounts. Highly stressed frame pieces are made of special chromium-molybdenum steel. At the rear, the old engine sub frame has been done away with. To gain a noticeable increase in stiffness, the rear frame was made an integral part of the entire chassis. The engine is now lifted out from above. Around the passenger compartment, the steel platform, rear bench, front and rear firewalls, and pillars are all welded directly to the tubes of the chassis. End result is that chassis flex has been reduced by 25% and torsional rigidity has been increased by 12.5%. Other chassis specifics as noted by Ferrari:
1. Weight reduction of 40kg/88lbs;
2. Lower center of gravity;
3. Reduction of unsprung weight;
4. Steering points in aluminum alloy;
5. New steering column shaft design;
6. New steering rack with longer arms and more direct ratios;
7. New steering moment offset;
8. Bilstein gas shock absorbers with aluminum body and adjustable plate;
9. New shock absorber settings;
10. Lighter weight springs.
Gearbox and Differential
1. Limited slip differential (40%) with reduced axial thrust to increase reliability;
2. New transfer gear ratio;
3. Strengthened transfer gears;
4. New synchronizer pre-loading springs;
5. Gear shift lever housing with sliding ball bearings;
6. New selector and modified gear shift lever inclination;
7. New single plate clutch with reduced inertia and asbestos free clutch linings;
8. Entire gearbox and transmission strengthened throughout.
Brakes
1. Larger front discs, 315mm x 32mm, with cross drilled braking surface;
2. Larger rear discs, 310 mm x 28mm, with cross drilled braking surface;
3. Aluminum calipers with larger pistons: front 44/40mm; rear: 40/36mm;
4. New ducts for brake cooling;
5. New brake proportioning valve;
6. Brake pedal ratio is more direct;
7. Redesigned hand brake with reduced application effort.
Wheels and Tires
1. Front wheels increased from 16 to 8 x 18 with 235/40 ZR 18 tires;
2. Rear wheels increased from 16 to 10.5 x 18 with 295/35 ZR 18 tires.
Styling Changes
1. New trapezoidal shaped air intake scoops on front with prancing horse;
2. Body colored front spoiler;
3. New profile to the C pillar fins in the rear sections with elimination of vents in sail panels;
4. Integral air intake slots added to the engine cover;
5. Rear lights are now dual colored and a redesign of the underbumper to change aesthetics of the exhaust system and exhaust outlets.
6. Wheels redesigned;
7. Interior restyled with elimination of center console and repositioning of the corresponding instruments under the central part of the dashboard.
8. Door panels and armrests have been changed.
https://www.ferrarichat.com/forum/threads/testarossa-to-512tr-differences.307199/