With H&R SS, most likely you will need either CC plates.. or if you're on a budget- camber bolt kit at NAPA. $12 each. you'll need 2. They don't give the adjustability of CC plates, but most mustang drivers don't take it out to the track for road racing and therefore don't need the adjustability...
LOL, I thought u were going with the dynomax mufflers already?
If you get it welded for free, I'd say go with those and H&R SS. If you're on a budget you don't need CC plates, but rather a little bolt (forgot what it's called) that you can get at NAPA that'll return the alignment back to...
I have a steeda, and if I could do it over again, I'd try out the MGW. Steeda is a bit notchy, which doesnt bother me much.. but the MGW allows you to angle the shifter close to you. Ford messed up with their shifter placement on our cars.
I was pretty set on going with a Magnaflow catback, but Summit (and other stores) are having rebates on dynomax mufflers which makes them really cheap ($15 for super turbos and $20 for ultra flo). I'm looking for a sound really mellow (cops in So Cal don't mess around) similar to the Magnaflow...