[kfdon]

This thing is a monster and the largest piping available for the FD. It is a midpipe back exhaust, full 4" piping which is SS and flows into a full titanium canister. The piping on this exhaust is fine, however there is an indenture on the bottom of the canister along with some light scratches, these are NOT visible when installed and they do NOT affect performance. Unlike most exhaust setups from tuners, this is a single piece full exhaust so it replaces BOTH the catback and midpipe. It has been discontinued from HKS for a few years now and is still one of the most highly sought after exhausts made. I have just had the tip re-polished but left the pipe on its own as is, there is a butterfly valve for the exhaust if you would like to use an actuator to adjust flow but I don't have it hooked up. For big power rotaries only, if your not pushing enough through this thing, it will just hurt your setup in my opinion.

Video: HKS Titanium Racing Muffler Exhaust - Mazda RX-7 - YouTube

IF you can still find on, even in Japan in good condition your looking at least $1500+s/h and it's still used to give an idea.

$1200obo - It sounds steep, but any Ti exhaust from Japan over 3" will set you back well over four digits.

Some pics of the fresh polished muffler and hanger, titanium doesn't come to a bright polish like stainless so that is why it looks like that. With a rotary's heat going through it though, it will be blueish purple burnt in no time.
http://i105.photobucket.com/albums/m216/tai-lun/93%20RX-7/null_zps311d3494.jpg (http://s105.photobucket.com/user/tai-lun/media/93%20RX-7/null_zps311d3494.jpg.html)
http://i105.photobucket.com/albums/m216/tai-lun/93%20RX-7/null_zps4a63fe9f.jpg (http://s105.photobucket.com/user/tai-lun/media/93%20RX-7/null_zps4a63fe9f.jpg.html)
Notice the JASMA tag for authenticity and "Race Use Only" as advertised by HKS, not off-road use like most mufflers, but race-use only :D