That really REALLY sucks!
Talk to your insurance company, you might be able to get money for mods installed on the car, but it takes some talking (when I crashed my RS, I got 2 new sets of HELLA lights because I had a picture of the lights installed, and a printout from a website with the cost of the lights to prove how much they were worth).
For the celica, if you can prove how much similar cars sell for, they generally will give you that amount, instead of the blue-book value. Collector cars are tricky though (that's what Hagerty is for).
You can also sue the other driver if your insurance company doesn't. Depending on the state you can also file a civil suit or mini tort to cover your insurance deductible.