bbs rs help

[Quaser]

Im looking at getting some bbs rs's in the 16" 5x120 variety, and have a couple of questions:

What would be the ideal tyres to run (assume staggered 8j and 9j)

if they were on an e30 m3, what would be the ideal offset if I was to run 18mm adaptors, and would I need any arch mods.

my car is a e30 convertible, and I don't want to do a suspension conversion unless I can get one really cheap.

TIA

Q

[Quaser]

Anyone?