We have had pretty good experience with hpi bodies. The 68 camaro has been the best Ive used personally. We have used the HPI GT-350 Mustang, 69 Camaro and Cuda, as well as the pegasus 70 Camaro so those are the ones I can only account for.
The HPI bodies seem to have more realistic molding detail I think. The 70 camaro wasnt bad there but way over sized (was like a parachute). As far as durability the 68 camaro has done by far the best for us.....we spend alot of time finding the walls lol. As for 2 piece molds, I dont care for that part but when done right we havent had any issues. Even with spoiler when mounted right.....which isnt with designed mounting area lol.We havent had any narrow width issue with the bodies we have used with our TC5's. All but the the 68 Camaro are a little thin I do agree lexan wise. All my 68 Camaro bodies are still in really good shape after alot of races on concrete and carpet.
The Mcalister and Parma just seem too Bricky looking as well as the RJ Speed bodies. Lacking detail. Whether they hold up as well or better I cant say. But like you mentioned, from the driver stand they do all hold the spirit of the class look.