I would say spend the money and buy the actual shop manual - mine cost $125 from the dealer but it was the best money I spent on my sled! It will give you the step-by-step how to do everything on the sled as well as give you part numbers for specialized tools. Even if you don't want to do something yourself it will give you a better understanding of the sled and what exactly the dealer wants to do. The first time you decide to do something yourself instead of take it in to the dealer the book pays for itself.
The user manual is almost useless - mine says to take it to the dealer to change the chaincase oil for crying out loud! I suspect (don't know for sure) that your spark plugs are just hard to get to. The DI 2-strokes (e-tec engines) have to have the plug pointed the correct direction (indexed) to work right - the dealer has to have the correct size shim to get the plug pointed the right way at the right torque spec or something bad happens. I don't know if there is something like this going on with the ACE as well.
Was it the kill switch or the DESS cord that you had to wiggle? They can be finicky - I usually just leave mine on the sled and if I do have to take it off I will wiggle it really well when putting it back on. They are also notorious for getting a dime stuck in the socket if you put it in your pocket with a handful of change!
These sleds really aren't that hard to work on if you are mechanically inclined. They are tight and use more rivets than I like to see but if you think your way through it you can usually figure out how things come apart and go back together (shop manual helps!). You can do as much or as little maintenance as you want with the caveat that only a dealer as the equipment to connect to the computer. Last spring I had a check-engine light come on and it cost me $25 for the dealer to hook it up to the computer and pull a report. Really amazing all the info you get out of it though - well worth the money!
Good luck and have fun with it! Show us some pictures when you get a chance.
PS - if you change your own chaincase oil be very careful tightening the bolts back in - they are self-tapping into soft material. In fact you are better off buying a set of 6mm / 1.0 pitch bolts from the local hardware store and replacing them - just tighten to 'firm' with a 1/4" socket driver and no locktite! (That last little bit of advice cost me $70 from the local machinist to have him heli-coil all of my threads). Live and learn...
Here is me replacing the 's-module' after hitting a log a couple years ago. Next summer I am going to replace the 'e-module' - the next part in you can see below - another 'incident' with a stump:
Here is after I took the fuel tank off to check filters: