Not a bad set up, I'd personally go with Flowmaster. The 10 series muffler gives the v6 that v8 growl. I'd also do divorced duals instead of the cat back because of the better air flow and sound quality.
I've run true duals with flow 40's with the pipes out the back, and recently had them dumped before the axle. Sounds better now, but the same setup with thrushes and Magna flows sounds much better. My buddy and I ran ours side by side and his magnaflow gave a deeper smoother sound, unlike my tractor like flowmasters.
i wouldnt spend 800 on exhaust, you can do it FAR cheaper.
I had mine custom bent with 2.25 stainless and flowmaster mufflers with stainless tips for 350 out the door. Aim for 400 bucks for the budget see what you can find, also you have the Y pipe so you either have to find something that bolts up there and goes out to duals or modify the stock Y to work with a normal GT style catback that expect and H pipe~ (they make adapters or a shop can fab connections but make SURE you can unbolt the catback and its not just welded to the mid pipe)
__________________ 2003 Cobra Vert (Redfire) #3938 of 5082 @ 05/27/2003
472rwhp/493rwtq -Modification List - Dyno Sheet 2012 Mustang 3.7L M6 (Kona Blue) 2011 Ford Edge Sport (Red Metallic)