Lube up all your seals with a bit of grey RTV. Make sure everything is 100% clean before you do. Put a tiny bit of OIL on the seat that the o'rings go into and seat against. Now put some rtv on the orings and assemble very lightly, finger tight. wait 1 hour, now tighten down properly. if thats not fixing it then replace parts or upgrade. If its the boot, get some upgraded clamps vs the spring ones. CLEAN everything you put together with a rag that has some brake clean on it so that the oil does not let the boots slip off. DO NOT SPRAY brake clean or anything into the pipes, this will cause a run away for a moment or worse. Trust me, scared the CRAP out of me the first time i started it up after taking ONE pipe off that i cleaned up with parts cleaner, lasted 2 seconds. Not good but no harm i think.
Big 10.4 on the darkside kit. you have no idea how much work it is to replace it though, worth it IMHO.