I saw your car last night walking the dogs, very nice, I love how low it sits now. For some reason, even though I have the Eibach springs, my rear wheels sit higher than other e30's lowered (including other 318is).
As far as a cheap front spoiler try this link, it's cheap ($89 US) and looks great when painted, I had it after my stock one cracked. Unfortunately this one also cracked when the curbs were first put in our street#$%^&*! I would definitely buy again.
Included a picture, ignore the painted grill, ugly, but this lip spoiler is very subtle and not much bigger than the "is" spoiler. Also uses the same mounting hardware.