thinner tires on wider wheels will give better feel. wider tires will give more ultimate grip. just depends on what you want. also, the larger the stagger front to rear in tire sizes the more the balance of the car is changed ... 225/35 17 front and 235/40 17 rear would tend towards oversteer and 205/40 17 front with 255/40 17 rear would tend more towards understeer. It's not that the car will necessarily oversteer/understeer too much, just that the balance is changing in that direction depending on tire size choices.
I like the 9 rear because it allows more options, like 255's if needed in the future, and because it stretches smaller tires like 235 and 245 (more than an 8) to give larger/better contact patches and better feel. I like 205's for a 7" front for feel, but that is the direction I typically go for personal preference. For a street car or street wheel/tire setup I prefer better feel vs more ultimate grip (to a certain extent .... 185's would feel better, but that's a bit extreme).
for the ntr, I would do the 17x7 +40 with 205/40 17 and the 17x9 +45 with 245/35 17.
The ATech's look good and if somebody has them in mr2 sizing the price is certainly right.
