Rims are the same size/weight as stock, no rubbing even on speed bumps, gas milage is the same. My only complain is that the tires are runflat and it is a little heavier/harder than stock but I got them cheap at ebay ($450 shipped for all 4 brand new). I might try the Generaltire Exclaim when the Goodyear wears out, it is highly rated at Tirerack and light/softer.

 

Yes, they are wider, but 40% of 245mm is very close to 45% of 225mm, so the overall diameter of the wheel and tire is very close to the same as stock. So even though you're running a 40 instead of a 45, the sidewall is still virtually the same height as the stock sidewall. Get it?

The plus 0 business is because you aren't upgrading the diameter of the wheel / tire package (ie. going from a 17" wheel to an 18") nor are you upgrading the width of the wheel. just putting a little wider tire on the same size wheel.

 

I have the OEM Dunlop SP Sport 8090's on my car now and am really happy with them. When I need new tires, I think I will go with Dunlop SP Sport MAXX in 245/40. They are Tire Racks #1 rated max performance summer tire and are almost $40 cheaper per tire than the 8090's that Tire Rack also sells.

 

My speedometer with stock 225/45 tires shows a little fast, it show 77 when really going 75. If anything, 245/45 may make your speedometer more accurate. To check your real speed over a measured mile (mile posts or odometer check section), time how many seconds it takes to drive the mile, divide 60 by the seconds it took to go the mile, and multiply that by 60. It works. If it takes 50 seconds to go 1 mile, 60/50 is 1.2, times 60 is 72 mph.