The VW Golf TCR was available in the XB1 beta test as well.
I hope the MG TCR makes the cut. It's a less common TCR model so that makes it more interesting.
In single player/private multiplayer can obviously do whatever you want, but the way they showed the featured multiplayer and the way these reveals are going, I'm afraid the "spec" racing will just be "homologation but only 1 build per car." Kind of a shame as some of the cars end up too far away from their original specs and it makes them not great to drive.
I know I already mentioned it in this thread before but the TCR Audi in FM7 was the perfect example. Wonderful car to drive in stock TCR spec, less so when it was upgraded to compete with the TC1/NGTC/SF cars in the "Forza Touring Cars" division.
Makes me wonder about Forza GT as well. If they try to shoehorn GT4, Super Trofeo (of the Maserati and Lamborghini varieties), Ferrari Challenge, VLN SP3T, borked Super GT GT500, GT3, GT2 (pre widebody and post widebody), GTE/GTLM (pre aero update and post aero update), GT1, and possibly the Porsche Mission R as well... The class is likely to be a mess again.