Welcome aboard. I have a Marauder in .22, and did the Hill upgrades. Before you get too deep, decide what you want the gun to do. You can tune a Marauder for more shots at lower power, fewer shots at higher power, accuracy or everything in between. I did the accuracy / slightly lower power / more shots per fill. About 870 fps with the JSB 15 grain pellets. Now getting 50 shots per fill. Great combination for me.

Marauder is a great platform. Great for shooting as it's accurate and has a good trigger, and great learning platform. Have fun with the hobby!