bead rolling pipes at a shop will run you about 5-10 bucks a bead.. depending on how well you know the guys at the shop ...
i didnt do this... i use an exhaust cone or a 2-1/2 inch steel cone literally looks like an icecream cone turned upside down .. just take and smack the pipe onto the cone 3 or 4 times, and voila, you have a flared end ...ive seen many ways to keep the couplers from blowing off..
you can tack weld a dot in about 6 places arround the pipe bout 1/4 in from the edge...
you can take an adjustable wrench and just put a tweak, outwards, in about 6 spots arround the pipe ...
or you can use a 1/8 inch tipped punch, and put dimples, from the inside out, in about 6 places arround the pipe.. again about 1/4 inch from the end of the pipe...
all you want to do is make a ridge or "bead" you can stretch the coupler over so that when you tighten the clamp up arround the pipe you would have to slide it over the ridge or bead for it to pop off... this will completely solve the problem as long as you do ALL of your silicone connections on all of your pipe
a good exmple of what were saying, is the raised edge your throttle body has to keep the boot on...same thing but you gotta do all the pipes to hold any kind of boost pressure....
hope this helps ya ....Joe