I have to say that the 'engineering knowledge' displayed in many of the postings here rarely fails to amuse me. With the complete and utter nonsense which some people trot out they thoroughly deserve to be financially raped by the less scruptulous Part M companies that thrive in the UK.
Having completed a double engine swap in a day ( two aircraft, swapping from one to the other) and flying both the next day after sorting a couple of non standard mods and the paperwork, I can only say that sometimes less is a lot more................. and some basi spanner skills are all that is required - oh and actually reading the manuals, rather than doing what you did on the last one.....