All GTRs understeer, so in the end, the supra would out perform the gtr in circuit racing, and consider all other aspect during that race, its not gan-san, his a pro at driving, at lest his trying. Toyota is more into pro racing, than nissan is, beside Super GT, but nissan has more aftermarket things backing'em up.
The Silvia's+180sx, Skyline series, and others cars that i havent mentioned (pulsar GTi-R) have all being heavliy modified by famous tuners.
toyota only has the hachi-roku, supra, ae111+ae101, jzx81,90 and 100.