I have now done BTB testing with the Mk2 HP Golf. Removed the plastic bushings and installed the DRS.
Increase of solid 2-3 MPH @ Apex and exit V. Much better tire use.
The solid rear bushings and very hard springs are out dated at this point for the Mk2-4,.
The Mk 1 still has axle bushings that are too small to get much axle travel.