i totally agree with you - making an earlier model gtr quicker than the 35 in a straight line is not hard & can be done for less than 25k (with the right supporting mods, no short cuts etc). you just need to weigh up the costs though.
for example, lets say an r34 costs you 60k + the above mods = 85k circa
these days, u can pick up an 09 gtr for under 100k (not much difference really)
if u want a 'nicer' & newer model car which u wouldn't need to modify, unless u wanted to fly to the moon = r35
if u went to a vs2, that would definitely hold its value better & in some cases, appreciate like the nur - just like the ADM R32 gtr