I have available a Prodrive Axleback, Round tip.
These can be oval tip, standard round tip and large round tip.
This is the large round tip.
It flows very well and is quiet.
Prodrive parts are expensive, because they are well designed and made of quality materials.
Here is some info that I collected and stuff I noticed, during my ownership of this:
-The silencer perforated tube extends all the way into the tip. The tip is therefore ... functional.
-Every time you look at a 3" exhaust, when you measure the inner diameter of it, it's 2.7"-2.9". The Prodrive 2.5" is close to 2.5" inner
-The Subaru Sti titanium axlebacks have a welded inside diameter reducer and the inner tubing diameter is 2.25". There is no diameter reduction in the Prodrive, that's not how it silences.
This is why this flows very well for the 2.5" class of exhausts and still is quiet.
This is in good shape and does not leak.
I will include a gasket I have around, that may work with this, but my advice is for you to re-use an OEM gasket, or buy one.
The price is $280 plus shipping.