Did the search thing and checked the 2q/zq site and couldn't find the answer to this particular question. I recently purchased a hennesy with a #3 mod. Is it possible to upgrade to a mod 2 or 4? and if so, what would be involved cost wise?

I haven't given the mod 3 a test run yet, but I suspect I would be happier with the 2 or 4 although the 3 is still a vast improvement from the stock velcro bottom entrance IMO.