I'm sure this information has probably been passed around, but I can't find exactly what I'm looking for right off-hand. Where can I buy the 9mm drop-in barrel for my XD-40? Are there different/more reliable brands? Any idea how much they cost? Also, once I do get this barrel in, do I also need new 9mm magazines? Seems like I was reading that I can just pump my 40 mag full of 9 cartridges. True?