Haven't been on RC Tech for some time (partially due to the broken VTA thread). Glad to seen there is a new working thread so I can view oldest first.
The issue of "Will 'x chassis' make a good VTA car?" comes up a lot. If you are a decent driver, any chassis that can get at least a 3.8 FDR will work in VTA. TT-01's and HPI E-10's can be used in VTA, but the TT-01 will require either an aftermarket motor mount or will need the F201 spur gear to get close to a good FDR. The HPI E-10 will at least require oil filled shocks, but HPI E-10 upgrades are really too expensive.
I was able to set TQ for the 1st 2 rounds of the final leg of the Hurricane Series last weekend using a TC4. I even had a blown out/no oil left front shock. I had been tied for 1st in VTA for the series, but had a bad final race to drop to 5th overall.
The only reason I don't still run a TC3 in VTA is that the TC4 is easier to adjust roll centers on. The TC4 also has proved more durable for my aggressive driving style (I like to hug the boards/corners). I wish there was a gear diff option, but the ball diffs have served me well.
Bottom line, don't be afraid to use an older TC in VTA. With a decent setup and good driving any car can win in VTA.