I've been reading everything I can find on clipping and frame construction because I plan to roll my own.
The subframe approach is a lot of work, and if you are paying for that work, the shops say its cheaper to use the MII approach.
A log of guys complain about alignment or strength issues related to subframing. Most of those are quality of workmanship issues, and I've seen some very similar complaints about the MII approach.
Swapping an entire frame is a lot of work. So is building your own frame.
I've come to the conclusion that none of the answers are perfect. I've wanted to build my own frame since I was a kid. I've spent enough on tools to pay for a cheap crossmember and junkyard parts, and I'm not done yet. For me its about wanting to do it myself, so I'm doing it my way.
Give me another year or two and I'll tell you how it comes out...
