Cecil, if I bought a 172 I do get the cruise speed, however if I lose my medical I can't fly it and I can't maintain it either.
I can still do Melbourne to Broken Hill in a day (still air + stop at Yswh) which is about my style of flying anyway.
The STOL thing is important to me because the plan is to keep it at a country property.
God willing, I'll put in 30+ hours a week and have it flying in less than a year.
While I will enjoy building it, the purpose is to use it for both fun and transport where possible
For example, Mansfield, where I once had a country property, is Three hours by road from Melbourne, and the Sunday afternoon drive back to the big smoke kills a lot of the enjoyment. By C172, Walsh's strip at Mansfield is 45 minutes from YMMB.
The Dynon is going in because with the addition of Two servos you have an autopilot, and once you have had an autopilot you won't want to fly (Tour) without it.
Well, that's my reasoning anyway, fire away...