Hi bbryan, since it's a new engine and you have it I'd install it and fly it for a while till you can upgrade, My model III kit was produced in 1992 first flown in 1993 I purchased it in 1997 with 20 hrs flew the 582 to 297 hrs without any real problems(I like you never truly trusted it but it run fine). At that time I installed the HKS 700E that was the best money I've spent on the plane, don't believe for a minute that the 582 is a cheap running engine or that it is simple and cheap to overhaul, regular maint counts up and a true overhaul is not cheap and operating beyond the Rotax TBO is like playing with fire it can be exciting but in the end you'll get burnt. The operating cost of the HKS is less than half of what it cost to operate a 582, a true overhauls is less than half the cost of the 582 plus the HKS TBO is now 1000 hrs. The HKS 700E is a true 60 hp engine that burns approx 3 gph, runs smooth and quite have an electrical system that is quite so you can hear and talk on the aircraft radio and the installation weight is 7 lb max more then the 582 with the proper propeller it preforms as well as the 582. I now have 400+ hrs on the HKS and would never go back to a 582.