This is probably of very limited use in helping you make your decision, but for what it's worth:
Cosmic re-shelled my UE TF-10's for me, and over a year of daily use down the line, I still couldn't be happier.
Despite adding a dynamic driver to the already fairly complex triple drivers of the TF10, the overall sound signature has changed little (going by memory here) except for the bass frequencies, which have a little more presence generally, and do a great job with music which relies on the bass frequencies.
I was the second customer to volunteer (actually, badger is more accurate) for the added dynamic driver, and probably benefited from the experience of the first, as he decided to revert to a straight reshell, which I seem to remember reading that he was very happy with.
I think that anyone who can accomplish a good hybridisation of an existing IEM is likely to have little trouble with most straight reshells.
This is just one anecdotal data point, but I'd say go for it.
have just sent my Legend R to be reshelled by cosmic ears, am looking forward to the end product!