I consider the work that I do to my engines as personalizing...
I'd love to have a Jett .56 LX but spending that kind of dough is cost prohibitive at the time. How much are they...350.00 or so?
I have several Nelsons of various sizes...dozens of K&B 6.5's and 7.5's and over a dozen Super Tigre X.40's, X .45's, and X .60's so just speaking for myself, I know what a well designed engine looks like and specs out to...
If you can take an 80 dollar engine like a TT .46 or Evo and get to within 85 - 90 percent the top r.p.m. of an engine that cost 3 times as much, and it is still tractable, then the time spent modifying it is time well spent, IMO.