To avoid confusion/flames, I have searched already and couldn't come up with anything like my situation.
I just received a vehicle inspection notice from a local cop, 30 day time limit.
I'm looking to bring my exhaust volume down quite a bit, and here's what I currently have on my 90 GXL:

RB collected header
no cat
RB turbo Y-pipe
universal straight-through mufflers.

This particular setup mic'd in at approx. 145 db's peak.

Locating stock parts is difficult unless I go through the dealer which is going to be very expensive.
So I was wondering, would there be a fairly noticeable difference if I added a cat and changed the mufflers to the RB turbo models? I know that they are a straight-through design as well, but they're much quieter on my friend's turbo than my mufflers on the NA.

i'm kinda hoping that a cat on my car would muffle/restrict the sound close to the same amount as my friend's turbine does.

Thanks for any input in saving my *** and keeping my mazda dream alive...

 

your ideas would definately quiet the car down alot.

 

Keep in mind, the same muflers will be louder on an n/a. Turbo cars have a turbo and wastegate which quites and cancels alot of the exuast noise... A turbo is a mute compared to an n/a with comparable exhausts.

 

I could trade you a RB cat replacement pipe and silencer for the header and what ever you have between the header and y pipe