Is a 225/50/16 going to be the tire you're going to run?
If it is, there's really no reason to use a 16x8". The measuring rim for that tire is a 16x7". A 16x8" will work, but the tire will probably look a little stretched. Now if you were going to run 245/50/16 I'd say the 8" rim might be worth it, since the measuring rim for that tire is a 7.5".
Are you planning on the same rim in the front? Because a 5" backspace in the front with a 16x8" is going to be really close to putting the rim into the suspension. A 16x7" with a 4.5" backspace would be an easier fit and would keep the rim centerline in the same spot.
