Adding Weight or ballast in the trunk.

Just a thought.... Sandbags.
Can't be loose ballast or any liquid. You can use steel/aluminum battery/ballast boxes. The boxes and/or steel bars have to use a minimum of two 1/2" grade 8 bolts mounted through the frame or major crossmembers per 100 lbs. If I find some pics, I'll post them.

I do have some new aluminum bolt-together boxes available, but don't know how much they would be to ship.

Despite extra weight, ballast can help win races by providing consistency, especially at marginally prepped tracks.