The exhaust can come three different ways.
From the corksport website;
Corksport Cat-Back Exhaust - $440
This requires you to cut your exhaust after the second catalyst. The advantages of this are the fact that its the cheapest option and allows you t keep both stock catalysts. The downside is that you have to cut your stock exhaust.
Corksport Cat-Back Exhaust w/ Racepipe - $520
This option requires removing your second stock catalyst, however makes it so you do not have to cut the exhaust because this will bolt on to the joint between the two catalysts. Check with you local shops to see what your emission laws are. Not have both cats may cause you to fail emissions.
Corksport Cat-Back Exhaust w/ Racepipe and High-Flow Catalyst - $720
This is the same bolt on concept as with the racepipe, however this one replaced the catalyst that you removed with the racepipe with a high-flow catalyst. This is the most expensive option, however will allow you to not worry about passing emissions tests.
I do not know if Corksport offers any sale prices at all.
I haven't purchased mine yet, but I plan on going with the third option, with the racepipe and hi-flow cat.
Hope this helps a bit.