i just bought a STS D28M .28 engine off e-bay from a flordia dealer ( faster shipping )
i got it cus i've read alot about it here, and everyone says it's a direct drop in.
but will my flywheele, clutch bell and stuff fit it?

It should.

i plan on running 20% nitro in it but what oil % and what glow plug dose this take will OS#8 be fine

Ths STS D28M takes standard glow plugs. If the OS #8 is a standard plug (not a turbo plug), it will fit on the D28M. I'm not sure, but if an OS plug has a letter "p" in front of the number (example: P4, P5, P6), then I think they are turbo plugs.

Try to buy one each of a hot, medium, and cold standard plugs so you can advance or retard the D28M's timing according to outside conditions. You can then tune the needles normally for performance.

I'm not sure what rating the OS #8 plug is; you can search on-line at OS's web site to find out what type of plug it is.

O.S. #8 is a strandard glow plug, with medium hot rating. it will fit the sts engine, unless it uses turbo plugs.

Thanks! I have OS stuff but I could'nt remember which the #8 plug was.

i don't think it's a turbo motor, at least it wasn't listed as one.
i'm just hopeing my clutch bell and stuff will work.
thanks for the replies.

Ths stock HPI flywheel and clutch assembly will fit the D28M. The STS has SG shafts and that is what is needed to use the stock HPI clutch assembly.

thanks for all the help and savage jim, you've awnsered alot of my questions, thanks.
if you we're in missouri i'd discount you some tattoo work LOL