as above, you only run low comp when you've reached maximum power for a set engine potential, i've run over 200bhp on standard internals, as reliable as any other engine i've run too.
low comp is more laggy as said, plus uses more fuel also, basically needs loads more boost to get the best from them.
find a good known complete engine and fit it, you can spend a lot to sort a bottom end plus gaskets etc. just get a working engine for around £400 ready to roll.