STS Wheels on the CTS

Hey guys, before you skip this thread and say use the search function:banghead: ...I have already researched this but found some conflicting information and a lot of it is several years old. I have the opportunity to buy some 18x8 chrome 14 spoke wheels off of an STS.
http://www.wheelsandcaps.com/w_sele...CRETURN=&_YEAR=2008&_MAKE=CADILLAC&_MODEL=STS

I know the CTS can handle the 18x8's, but what is the final word on the 51mm offset? Will I be rubbing the suspension? What if I run a more narrow tire like a 235?

Or should I just bag the whole idea and go with these? I kind of like them better anyway.
http://www.mkwalloy.com/custom_wheels/wheels.asp?id=133#mkw-M71-Gun Metal

I remember WickedGoat saying he has access to a great wheel/tire compatibility guide at his tire shop and TX has run a bunch of wheel setups. Any input would be greatly appreciated!