For what its worth, I balanced my Wren MW54 kit as per the Wren instruction, and have run it over 5 hours in the past two months with no problems (so far!). My max RPM is 160,000 and it is super smooth at all rpms' other than a very, very slight vibration when passing through the 85-100 thousand area. I attribute that to some harmonic vibrations as it is only at that rpm range. So far my bearings are as good as the day they were installed and I have not heard any squeels or whathave you.

I am interested to see what lifespan I will get from mine, and compare it to the life of a factory balanced rig.

What do one of you guys here in Canada charge for a balance?

One note here before I forget: when I got the kit for the MW54, there was a small white paint mark on the compressor. I left it on when I did my initial balance. Then after running the engine for the first 6 to 10 runs (approx 5 to 6 minutes per run, maybe one hour running time total) I noticed the engine was not as smooth as it was originally. After inspecting the parts, I noticed that most of the paint was gone off of the tip of the compressor blade! This small amount of weight was very noticeable indeed, and I had to strip down and rebalance - getting back to my original smooth runnings where it remains. Just somrthing to look out for anyone who is building one..

Andrew Coholic