Are you talking entirely stock R34 vs BPU??
I've been asked my opinion on this a number of times since driving a stock (and perfectly maintained) R34 round Japan last October...
I always sum this up as:
- 2JZ GTE > RB26DETT (stock RB26DETT felt slow in comparison to my BPU TT6 - and the BPU equivalent RB26DETT R32 I drove round Fuji Speedway didn't have the torque, but better response... personal choice I guess there)
- R34 handling > Supra handling
- Interior design / Quality is WAY better in the Supra - another league
- Styling - personal choice
- Engine / Exhaust note - personal choice - I love the sound of a 2JZ, but a properly tuned RB26 at full chat is a special sound
For me, you can tell the Skyline was more of a sports car when it rolled of the production line than the Supra - although a Supra can be pulled to the same level with ease (and most have done so).
As with any of the Jap 'tuner' cars, you can modify to such an extent all of the above goes out of the window.
I am just trying to give my personal assessment based on experience of BPU TT6 vs stock R34 GTR and 400+BHP R32 GTR.
I wouldn't sell the Supra for one, but maybe on my next stint in Japan I will bring an R34 back to sit next to it.