can anyone give me some info on the TT54S 4 stroke? (performance,durability,etc.)

I had one of these a while back and was quite pleased with its performance...but it wasn't quite enough for what I was using it on...had to go a bit bigger. I was using an OS "F" plug, 10% nitro fuel and an APC 12x6 sport prop...it ran quite well with that combo.

I hope you work out your situation.

Try doing a SEARCH.
There is a fair amount of info.