Tekin, i dunno how serious you are with that last post but geez you float some terrible information around
Why would a good flowing exhaust have 4 lots of restriction in it? (Cat, res, hot dog, muff)
Rav: Youd want something with a Catalytic converter and a rear muffler/cannon (if you like sound)
If you dont like sound as much go for an exhaust with a cat, middle resonator and a rear muffler/cannon.