Congratulations on the CV7's...they were my second choice as I have the Vossen CV3 and this is MYISF
setup based on feedback directly from Vossen:
Front: 20x9 +38 (Michelin PSS 245/30/20
Rear: 20x10.5 +45 (Michelin PSS 285/25/20
is correct that 255/30 and 305/25 match the stock size diameter better but Vossen never talked about those sizes...they said "if I don't want any rubbing problems" than go with the above...oh and I am on stock suspension and I love my fitment! See for yourself below!