I have no experience of tuned pipes or onboard glow with MDS engines, but we have been running an MDS .40 in our club trainer for about a year now. I have also read a lot of negative posts about MDS. However, our experience so far does not in anyway correspond to what I have read in those posts. Our engine has proven to be one of the most reliable, quiet and cost effective model engines I have ever come across. It is not the strongest .40 I have seen, but certainly good enough for our trainer. That is the most (and only) negative thing I have to say about it.

I have no real idea why so many others seem to have had bad experiences from MDS engines.