wheels for a 3rd gen

[Bsporty]

Soooo...I got my income tax check and I want to get wheels for my car...I am scraping the bucket at $1400.I really love the Petrol Vengeance wheels but they dont come in the sizes I want.I want to do 19s out back and 18s up front.I am looking for a hot mesh wheel for my '85 Z28.I have seen lots of guys using BMW wheels but im not sure what I would need to fit them on my car.ANy suggestions are greatly appreciated!

[LSx_88_Ciera]

what width and backspacing

[Bsporty]

Im looking at the RPM R-505's...they are really inexpensive but they were exactly what I was lookin for.
http://www.wheelstudio.com/view-wheel/rpm-wheels/r505-hyper-silver-with-polished-lip/wheel-size-all/wheel-bolt-pattern-all/wheel-price-all/vehicle-all

Looks like they come in 18x8
5x120.7 with a 20mm offset and 19x9.5 for the rear 5x120.7 with a 30mm offset. I know I am gona need me some spacers but Im a little lost...
unfortunately I still got the stock brakes... :(