Hey man,
I had the same offsets that they are going to give you, except I ran a 235/30/20 front and 275/30/20 rear cuz I wanted a stretch since my car was slammed on tanabe coilovers.. if you are just getting springs I wouldnt recommend stretch tires..
get a 245/30/20 front and 285/25/20 rear! those are correct..
btw I work at Vossen, if you decide to go with a set let me know, I can arrange a photoshoot with your car and have it featured on our company website
www.vossenwheels.com
-Jay