I'm in the same boat here and the costs do add up quick. I just ordered rear TCI suspension set up, mini-tub kit and I'm in for almost $3K so far. I still need to narrow my diff a few inches, replace axles, disc brakes and then buy wheels and tires. 18X12 rear rims are going to run damn near $3K for two rims so I'm going to be into my rear suspension and big tires for close to $10K.
PT cars ain't cheap.