Forget the suspension tweaks for now. The 400E is completely under-tired in my opinion on the OEM 195/65/15. I really like the way it handles on 225/50/16's on all 4 corners. That is the limit for width on that car and it really makes a sport sedan out of it. Check out the picture of the silver 400E in the Featured Cars section of this website.
http://www.peachparts.com/images/400e_front.jpg That is a 93 400E with 225/50/16's.
Do the wheels/tires and let me know how it works for you. Then we can talk suspension tweaks. As for specific tires, let me know your priorities and I'll be happy to discuss the options.
Congratulations on your new car....Lee