I think you have this easy from what I just added up. basically take out your cost of the parts truck (just don't add in the 200). You can put the apc seat back in, if you purchased two, half the price, same for the blazer seats, if they are separate, split the cost in two. I think I ended up with just over 1700 for the build based on your numbers. You can also run the drags and autocross with no exhaust, that would reduce cost and weight. You just need to remove it before you run, it does no count if it is not on the car, you can drive to the even with it on.
