Pre-silencer or not?
 

If I can avoid using one on my stockport's new exhaust, that would be helpful. I need to be mega frugal. How loud would it be? I can tolerate it to an extent. My friend has a 13b turbo BP with no silencer, and it's pretty loud, but surely a stockport wouldn't be nearly as loud, right?

I think that turbos normally quite down the exhaust alot, and a stockport with no presilencer will be LOUD. If at all possible i would try to grab a silencer. Alot of them shoot around on the for sale section so keep an eye out

Details of the rest of the exhaust system? Depending on the size and what you use as a main muffler, it might be tolerable. It'll certainly sound worse without a presilencer, though.

I know how it is, I was in your shoes just a couple of years ago (still am, to some extent), but take it from me: when it comes to rotaries, a cheap exhaust is not worth having. Use only Racing Beat heavy wall pipe and quality mufflers like Borla, Magnaflow, or Racing Beat, and you will be much happier with it in the end.

I got the RB header and 2.5 exhaust, with a borla under the car and a cheapo ebay on the rear. It isn't TOO loud, but it does have a good tone. The Ebay muff is falling apart though, I was much happier with my Mazdaspeed exhaust instead.

I have the RB power pulse muffler with no presilencer. It's RB header-straight pipe-RB muffler. Sounds maybe a little louder than stock driving around town but it wails beautifully in the secondaries. Mine is kind of raspy just because of whatever crap piping was used by whoever welded it all up(Before I owned it)

I can't really decide what size. I was thinking either 2" or 2 1/2", but I don't know if the latter is that nescessary. For the muffler I'm going to use one of those stainless magnaflow ones. I would go for racing beat stuff, but It's sooooo expensive. Do you think maybe I could just use two of the same mufflers in the exhaust system? (well, except the rear one would be a dual outlet)

You can find used RB mufflers for half the price here on the forums. One magnaflow will be rediculously loud

One Magnaflow, especially if you do 2.5", would be painfully loud. Two might be okay. Since you're not ported, I'd suggest sticking with 2" pipe, very preferably .120" wall. That will help reduce noise.