Scroll down to Neema's post #470 - he was running 285/35/20 F and 315/30/20 R R888s. Those tires are less than 1" taller than OE Boss sizes. I agree with people about running shorter tires - the Boss gearing is already short enough. Plus, shorter tires aren't going to be your friend on a street driven car unless you run a tall ride height (which looks goofy with the short tires).
http://www.svtperformance.com/forum...hread&p=12576105&highlight=neema#post12576105
http://www.svtperformance.com/forum...hread&p=12576105&highlight=neema#post12576105