Modding a Tarmac Works car into track ready racer

I modified a Koenigsegg Agera , Carbon edition, from Tarmac Works into a track worthy racer.  When I got it, i opened the plastic case and broke a side mirror off, so I already killed its value, so why not just mod into something I can race.  The ride height looks bad, but I did that on purpose for ground clearance.  It actually works very well, i just need to add some weight to the rear because right now it likes to spin kind of easily.