will 17's fit on a 98 hatch without any hassle ie with no arch modification etc needed? and if they dont will 16's. and how much can i lower the car on 16's or 17's and still be able to drive it comfortably and without hassle

It'll be fine man, just MAKE ABSOLUTELY SURE that if you plan on lowering your car, to get a wheel with an offset that will allow a proper lowering job without the rub, been there, it sucks...Scrape, scrape, Scrape. but 17's will be fine, just watch that offset.

My bud has 17 inch Konig Tantums with ST lowering springs, the 2.3 speedtechs, and he has some problems with the fronts rubbing the plastic wheel well lining over bumps and such. You'll be fine with a 1.8 or so drop.

Even if you would have problems with the wheel well guard, just take it off, that's what i did for my rear wheels, and it improved, but it'll still rub because of the metal itself, i have to work on bending it back, there is a machine that will do that without busting the paint..but get a correct offset, i think it's 39-42, dont' quote me on that, and you'll be fine....