Hello We have a quite a few TT25's and 36's (and the 32 and 39) and they have different cases but the mounting and physical size is basically the same making swapping between them easy. The Magnum engines made in Taiwan are basically the same as the Thunder Tigers with visual differences. The plain bearing GP series 25's and 28's Magnums and TT's are like OS FP's , both smaller and lighter then the BB versions (my sons favorites for slow combat).
Regards Gerald