I'm thinking about converting my NASA GTI Cup to ITB specs and racing it as my primary car. I want to make this car much faster with as little money as possible. It's currently a mid pack ITB car, about 2 seconds off the pace at Sears Point and Laguna, and 4 seconds at Thunderhill due to the effect of lack of HP. I think the suspension is the weakest component of the car right now. The GTI Cup requires open diff, spec springs and shocks among a few things. I've taken apart one of my spare struts and the front springs seem about 1/3 as stiff as 300lb/in springs. They might be 100 to 150 lb/in.

The strut cartriges are Bilstein yellow sports. Fronts are P0032 and Rears are B0657

How stiff of a spring can I safely go with these off the shelf shocks. 300lb front and 200lb rear? Can I get these shocks revalved so I can run higher rate springs like most other VW racers?

I would also like to eliminate the open front diff traction problem. I'm ok with squirley and difficult to handle cars. I'm thinking that welding up the front diff might be the cheapest/fastest way to improve corner traction under acceleration.

Thoughts?

#37 ITB Capri and GTI.