i've put quite a few rebuilt motors in. for others and myself, mixed bag tbh
most problems are normaly in the parts around the engine you don't get so you need to make sure everyting else is spot on, injectors, sensors, radiator, hoses, wires and ancillaries.
as for rebuilt motors themsleves for road engine i prefer a 2nd hand low mialage heath engine for performance i'm not very trusting anymore, i will ether build it myself or if i don't have the timem or tolls to build the engine i will have it built by an engine builder i know and to my specks and won't touch exchange engines. had really bad expriances with them a few years ago. basicly been craply built with sub standard parts and not what was orderd so they promptly sparyed themselves over the road. worst one was a tsr engine that i put in a mates car it went boom twice before we called a f**kit and striped it ourselves then threw it in the skip as it was competly un servicable.
since then i prefer to source the donor enigne myself strip and check it beofre then sourceing all the parts myself and haveing them balanced ect before ether takeing it to an engine builder or putting it together myself. so you know exactly what you have and true assurance that it is top quality but it is the most expensive way to build or have and enigne built.
