I was fortunate enough to fly out to visit Klaus (link) at Santa Paula a couple months back.
That guy sure has a good time.
Besides letting me fly the Determinator, we spent several hours digging through his past experiments.
A personal favorite was his independent induction runner mod. Which replaced the stock continental carb and spider with a rotatary slide throttle (shown below) and independent fuel injection. Can you imagine if this kind of thing was legal in formula one?