I am gona go ahead and recommend you try going with a 18x8. You can lose some weight here and still go tall and wide. Try looking at tire rack.com for tires. Two sizes that will fit that size rim and still be near the orignal diameter would be a 225/40/18 or 245/35/18. You will find just about every make of high performance tires for 225/40 and you still have some good choices with the 245/35.