Some guys really understand tuning, others have trouble, and these engines can also be finnicky. I understand a lot about 2 stroke engines, how they work, and the modifications such as boost porting and reed valves. HOWEVER, I am NOT the best tuner, and I can admit that. There is also the issue of these engines all being different, and what works for one engine may not work for another (in regards to tuning, the point being that each engine requires individual tuning). The main issue with the ht engines though, is the unreliability of the parts. The upgrade parts are usually reliable, but not everyone can afford them. The stock parts are not always reliable. I have replaced every single component of my kit, including the engine, except for the sprocket and the clutch lever. And I don't ride my bikes as hard as some of these other guys do. I ended up going 4 stroke, and although my bike has required some fiddling and repairing, I haven't spent a ton on it since finishing it, and its never left me stranded yet in almost 3 months now. It starts on the first or second pull every time. The main reasons I feel its required anything more than routine maintenance at all is two main factors. One is the fact that I got the engine and some of the parts slightly used, and the other is my own personal error at times, due to the fact that this was my first non-kit build. But as long as you're not looking to go cheap or limited financially, I would recommend a 4 stroke kit over an ht. Just my personal feelings on the matter. Some guys love their 2 strokes, and I did too for awhile. They are fun, easy to put together, and cheap to start out. But I probably spent 3 times as much on my 2 stroke bikes as I did to build my 98cc cruiser. I'm never going back to ht's again.