You just pick the flowmaster muffler you want. For example Series 40, 2.50" in/out. You muffler shop will add the pipe needed. So if you want to go flowmaster then you just need to pick the series you and the correct inlet/outlet size to match the pipe size you want to run. If it were me I get these but to each his own. Flowmaster 42543 - Flowmaster 40 Series Mufflers - summitracing.com
There is a guy here local that runs a muffler shop and he advertises dual exhaust with glass packs for $120. You need to take into consideration the shipping charges that summit will charge. I would imagine that your local shop will be able to beat summits price.
edit* Since you are starting off fresh from the headers there is no need to try and find a kit, just the mufflers and header reducers are pretty much all you'll need. The muffler shop will build you a custom system so you can't go by the application list for exhaust components.