I know what you're referring to. But, I found only 4-Tec 2.0 the servo saver didn't help much to save the stock servo. When I replaced it the stock servo with a cheap metal gear servo it worked well. If it will fit on a TT02 with a good servo it might work well. I've never tired it in any other car.
If it doesn't work (because of it being mostly plastic), there are aluminum versions from 3rd-party sources, such as Integy, RPM, and Hot Racing (NOT that I'd ever recommend anything from the first two). The HR part is TRF48SH25.