RE: NEW ENGINEE
ive just got a STS .28 and i have finished 4th tank of break in. im not going to recommend this engine because i havent seen what it full potential is yet, however i have been impressed so far by the acceleration which is much better then my SH.28 and its still running lean for break in. also it quite easily lifts the front wheels if im not to carefull on the throttle.
I would not recommend the SH.28, i did get it running very nicely for around 2 gallons and it had no end of power but then without any obvious reason the conrod snapped. SH may have fixed this problem now or it might have just have been a problem unique to my engine but im certainly not going to go back to SH.
as for price both the SH and STS are very low priced engines i got the Sh for about £80 and the STS for £95 im not sure what that is in US dollars tho
I hope this helps your decision a bit