IMO, don't be a parking lot douche and you will be fine. The tests are full of holes and can be challenged and most likely beaten. Variables such as air temp, sled temp, snow pack (hard like a parking lot, fresh snow in the lot, the lot being plowed and showing dirt), weather (cloudy or sunny, wind). All of these play a huge factor in results. There isn't an accurate sound test available yet that is fair to the testee or testor.
Mule has stated this on many occasions and if you speak with Erik at VOHK, he will go on and on about all of the variables. Be prepared to talk for quite a while if you chat with him about it.
FYI, I have a XP800 with a tighter head, SLP exhaust and HPS can and it passed last year during the "tests" at 3600-4000 RPM. It came in at 81db. Anybody who has ridden with me knows that particular sled at WOT certainly isn't quiet. Also, IMO the sleds that I ride with that failed aren't annoyingly loud either.
The first thing to remember is that now you are your own worst enemy, so just be nice and easy. DON'T let them run your sled, you do it.