"lrp ai runner plus reverse esc" + lipo's ?
 

wondering if it would be a good idea to use my lrp esc running a 27 turn brushed motor with a 2s 5000mah lipo ? or would it just emit some lovely milky smoke ?

Should be fine.

just keep eye on ur motor temps, some have found brushed motors get hot when using lipos

It'd work fine, but there's no lipo cutoff on those, so make sure you don't run it too long as you've got to keep lipos above 6v.