hi there, don't know if you saw this but VDUB ENGINEERING has a kit suited for the type of application you need, have'nt use there product 'coz I'm form the Philippines but it's almost the same as what I'm using the only difference is we custom made my suspension, this is how I install my 17x7 Rota Toxxin with a +42 offset wrapped with 215/45R17.
http://www.vdubengineering.com/products/narrowcoil.htm
HOPE IT HELPS.
