Need Wheel info please

Hi all,

i recently purchased a 1999 A6. It has some aftermarket wheels(see i have read through the forums-Imolas4= not rims) on it which are junk. i have had one repaired another has a crack and the other 2 are bent. i just replaced the tires with 235/40ZR-18 BFGoodrich g-Force Super Sport A/S due to broken belts and they were a brand i hate. anyway i was looking for a better quality wheel to put on there. i dont have a bunch of money and would hate to get some cheap wheels and end up in the same situation. because i already have brand new 18" tires i need to go that size. so i was looking at some factory rs or s 18" wheels to throw on there but i am having a tough time figureing out which will or will not fit via the offset and stuff.

any knowledge in this area would be great or a link to point the right direction.

Thanks