RE: Does a tuned pipe make a BIG Difference?
LouW,
May I suggest you read Dr. Blair's SAE Paper on Two Cycle Tuned Pipe Design (Dr. Blair invented the two stroke tuned pipe about 1950 at Queens University, Belfast) OR If you can't find that; Gordon Jennings gives a good description of pipe operation in his "Two Stroke Tuners Handbook"
I think you would find them enlightening!