For the rat-rodders out there heavily modifying their Polaris RZRs or casual riders who just busted their engine case, we’ve got the stuff to give you those extra ponies or the parts/components you need to get your engine back up and running. But if you're speed drunk with eyes bigger than your stomach, don’t get too ahead of yourself. When you upgrade your Polaris RZR engine, be sure that the drivetrain can handle the added forces. So if you plan on jumping up to the more-powerful RZR 1000 engine or adding a turbo to your existing engine, we’d suggest running better-than-stock axles such as Turner Eagles or Cobras in addition to RZR 1000 differentials.