I know of a company that produces the control arms and k members. I just bought another set from him for my car and have had 2 sets from him a while ago. He does not advertise and refuses to, I don't get it.
I guess he tried on talk or on here but got hammered on pretty bad so he is fed up. I guess pm me or something, I can try to get you in touch with him if that is permitted. I weighed these things and the whole set knocks 15-16 lbs of the car. It is the same dude that is doing them for that Mavis guy so 11scdsm can probably help out too. )(Jason is his name) I don't think I can post pics but they are awesome. I must warn you to ask for them not painted because they look bad painted, good fabricator, bad painter. He has a post on the gvr4 forum for quite some time about them and finally started shipping out after like 2 years.
Anyway, I would like to see some sort of bolt on exhaust for a gvr4 that is 3.5'' for the big turbo stuff. I bought a used certified system but its beat pretty bad.