Hey Paul,
being "on a budget" and racing touring cars is not an easy thing to accomplish (although it is possible nowadays). Out of these two, I think the TC4 would the better choice for racing (e.g. more setup options), but even that platform is getting a little dated by now.
If you're open to other suggestions as well, you might also consider:
3racing Sakura XI Sport
3racing Sakura Zero S (= Hobbyking Turnigy TD10)
Spec-R S1 or S2
Unless you insist on a shaft-driven instead of belt-driven 4WD drivetrain...