Personally i'd be getting 3 quotes from local smash repair shops then drop it off when you have enough cash to get it done.
If you ever try to sell it in the future and a potential buyer notices that its been repaired and then asks for receipts only to find out you did it yourself it will never sell. Sure collect the suspension and rear end parts but leave the body work to an expert.
Lets get the ball rolling, takes all of 2mins and it's free:
www.Chipin.com
PS. As for whether cars like this 300zx should be allowed at our type of trackdays, it was 10th fastest on the day, does that mean the 9 cars faster should not be allowed either? I've been going to trackdays for nearly 10yrs now and its the first car to car contact i've ever seen, it was a mechanical fault that caused a freak accident. Nobody deliberately goes out on the track to hit someone else.