Couple Rim/tire questions

[Flicktitty]

Hey guys. I have some pretty hard to find 15X7? or 7.5" Epsilon Mesh rims i got for a pretty good deal. i love the rim but there just do damn skinny to put any power down. So i am looking at having the rears widened.

But here is where my questions come into play.

i want to run a "real tire" out back 275 MAYBE 285 (doubtful)
So i know i need to tuck/roll the stock fenders. to run anything that wide.

But i need to know if it is even possible to get these wheels widened. they are a True 2 peice wheel. So that should be somewhat easy. But how do i know the offsets won't get all fucked up and stick past the fender?

Also How wide of a Rim to i need to run a 275-285? 9"? 9.5? 10"?

anyone know a Good place to send the rears out to get widened?
Thanks ZILVIA!

Pic of the car/rim
http://i2.photobucket.com/albums/y47/flicktitty/MESTUFF/April005-1.jpg

[fliprayzin240sx]

Widen rims? Only way I know you can widen a rim is swapping out the barrell. For the most part, you might as well buy a new rim cuz it aint gonna be cheap.

10j wide rim with a +25mm offset should be able to fit 275 with minimal work on the fenders

[Hawaiian240]

I'm running 18X8.5 +25 in front with 245/35ZR18 and 18X9.5 +35 out back with 285/30ZR18
Fenders rolled and pulled.
Clears my coilovers fine.