Hi, I am relatively new to R/C planes. I currently own 3 airplanes GP Revolver with 75OS AX, Seagul Dual Ace twin engine (OS 55AX) and a H9 p51 150 (recently crashed!)

I want to get a plane for speed but looking for recommendation on model/engine combo, I was looking at the scale Sundowner model, can someone point me to post where I can get some advice or help on model/engine combos? something like 100-120mph I would be happy with.