I don't think that you'd want [205/] 50 series tire on a 16" wheel. The best would be a 45 series tire.

As for the bodykit... There are a few add on lips that are available for the 5th gen coupes.

1. Wings West RS Series
2. Spoon CF (or replica of it)
3. Tsunami T1
4. Si Lip (from autodynamic.com)

I couldn't tell you what sides and rear to get, but here are some places to check what you like...

www.extremedimensions.com
www.importfan.com
www.wholehyper.com