another pic
my other rst with a 3" scorpian(looks not like the above 1 huh

) its a 3" with a propper roll on teh edge
every scorpian ive had has had a propper rolled edge like this

(my frst)
the inside has about a 5mm lip round the inside of the tailpipe where the back box meets the tail pipe but im pretty sure most pipes ive ever had have this