You will deff need to roll the guards dude.
Those offsets are for gtrs which have a more pumped guards than gtsts..
Sell the rims,
And get offsets at min or 30 for a gtsts..
30 front, you might just have to roll it a little..
Anything below 30 offset, will just hit the guards easily.. plus it will look gay anyways.. lol
I reckon for 17inch rims, 32 offset front, 35-37 offset rear is best combination..
Plus you already have 9inch wide rim.. It will look phat!!
Btw is that 17*9 all the way around?
Im not to sure if the fronts will fit then.. AS in, it might touch your coilovers..
In short, those rims are for GTR's!!