Hello. I want to upgrade the performance of my Radwagon I believe it?s a 4. I love the size and look of my cargo bike but I don?t love the performance. It accelerates slow, my battery drains fast because I?m allergic to pedaling, it has no shocks, no torque with heavy loads, etc. if u experts had $1500ish to upgrade the hell out of this bike what would u do? P.s. I often break the 350lb limit by 50lbs. Thanks.