That will be wicked. A big help in getting the power to the ground. Because as we all know, that's the main obstacle SRT-4 owners face. And hopefully there will be room for improvement, even with 255 wide tires. I hope that wasn't a misprint.
The all-new 2007 Dodge Caliber SRT4 rides on SRT-unique 19-inch cast aluminum wheels with 225/45R19 W-rated Goodyear tires. Wheel hubs and bearings on all four corners are adapted from Chrysler Group mid-size cars for strength.
Well, from the dodge website the wheels are 19x7.5. Coverted that's 190mm wide, so the tire will probably be a +1.5 maybe a little less and that will be 225mm. However, if you can fit a +2.5 tire on that rim, then you can get away with a 255mm tire.
Those are tentative factory specs, so they may change sometime prior to production but I doubt it. I believe the tire’s being used is the Goodyear Eagle RSA’s. They seem to be the only tires Goodyear currently makes in 255/45R19.
I can only go by what were told, I guess well find out when the official Caliber SRT-4 production information is released.
PS. When I reread my post I realized they didnt match at all, sorry for the confusion