I can see excluding the lotus Elise chassis but to do the same to the 'teg R and the S2000, or their motors, makes no sense to me. if they are willing to allow >3.0L motors or other non-standard allowances at alternate weights (even if only in the originally equipped delivered vehicles and not swaps, which is not clear), why not do the same for these cars in STL?

the Boxter S might fit into STU, I don't know. but consistancy is needed in the application of the admittedly very new rules. and they need to stop changing them so damned often to let a class develop.