I know a lot of people use a solid 35mm roll bar in front, and a 21mm in back, but a lot of these people are also using the same size tires on all four corners. Currently I have 275's outback, and 235's up front(I'm buying some 245's to rpelace them) and I can pick up a set of the hotchkis bars a lot cheaper than they'd normally sell for(about $250 for the set, brand new) and was thinking this might help the undeersteer a bit, especially since I'll be moving up to 275's up front and 315's outback.