Hey man,
Sorry to hear about your loss, that really does suck, I wish the best for you and your family.
Also its too bad you deleted your posts, as they could of been helpful for other people in the future who ask the same question.
As for your " relatively expensive route" - which does not seem practical, but honestly as a car enthusiasts I don't think there is ever a actual "practical" or "cost-effective" route, I'm speaking from my own experience too, modding =/= practical/cost effective, oh well. Do put up a build thread when you get a chance, it seems like fun. There are a few that have gone before you with boosting the M44, off the top of my head I know xxxJohnBoyxxx has spent a lot of time working to boost his m44, and gave me a few pointers when I was also considering that route. Maybe you could search up his posts to see if there is helpful information.
Don't worry I won't be nice all of a sudden either, I stand by what I have said above.
Good luck.