I have no idea, I've never looked into modding it to be honest.  Guitarale, if you test them out and decide that you want the JH-1 (which again I don't recommend), I'd sell you mine cheaper than what you'll find out there.  But I think theres better wahs out there.  Now the more expensive JH-1B I've never tried.  Nor have I tried the digitech one.  I always found the digitech one interesting, but never got the chance to test one out.