It's really easy. 15mm deepwell, a vice, 15mm wrench and lots of brake cleaner. Now putting them back together is different. You have to torque the body to 28ft-lbs. Do them all exactly the same. I just did my old set and a set I put the new nozzles on. Cheap old pop tester I got for 79 bucks and 3550 to 3600 psi. Got some .15 hardened shims off eBay too. Everything works perfectly. Way less than the $400 they want for 6 stock injectors.