Anyone know the biggest size tire you can put on a 02+ X with 20" rims?
The rims is 20x9.0 and i want the biggest tire possible without any rubbing.

I've seen a guy with 265/55 tires on a '03 sport. I think you can go up to 31" tires with minimal rubbing. Go to www.eunos.com/tirecalc, enter the tire size you want and you'll see it's height. Speaking of 20s, mine are For Sale ;)

the guy im buying rims from said that i should put 275-45/20 but i wanna put 295-45/20. anyone know if it would fit. i dont want my tires to look like rubber bands, i need real tires that can tow and grip.

That big of a tire isn't going to look all that sporty. 275/45/20 aren't rubber bands by any means. In my opinion, if you're going to be towing, don't bother getting 20" rims with some big ole tires.