No offense here, buy your question is maybe the most common mistake or misunderstanding by do-it-yourselfers. Your question is equivalent to asking if you could take a fender off a Volkswagen and put it on a Caddy.
Faucets and shower valves are extremely unique by brand and model. The is Zero chance that you could take any PricePfister trim and put it on a Moen. Also, the mPact valve is only a few years old, so unless your tub is fairly new, it is probably not that model. There are still probably som choices of trim available from Moen which would fit onto your model. This is all that will be possible without changing the entire valve system.