I have been thinking about buying a caliber exchange kits from MidwayUSA but am worried it won't fit my gun properly. My P226 is a 9mm and I was thinking about buying one in .357 Sig. On MidwayUSA it doesn't mention a requirement for what caliber your gun is originally but on Sig Sauer's website they list the exchange kit as specifically for the .22lr version of the P226. The kit comes with everything I would expect to be different between the 9mm and .357 Sig but I don't want to buy one and find out the frame is built slightly different or there be some other reason I can't use it. Has anyone purchased and installed one of these on a caliber other than .22lr and if so does it fit just like it was meant for that caliber?