Yup, that kit is a nice bolt on kit that any shop should be able to put on for you.
Also if you send a message to AmericanMuscles rep on our forums they will give you a further discount, I think its 6% or something like that.
In the future if the cats go bad again you can simple buy two high flow cats and have them welded in place of the old ones and be in it much much cheaper then having to take care of 4 stock cats.
Now here is something to remember.
DO NOT LET THEM TAKE YOUR STOCK CATS!
Those are worth good money, right now the average is $40 dollars each, thats $160 dollars that goes in your pocket to put to the new exhaust.
Check the phone book and find a scrap or recycling yard and ask them how much they give for Ford Medium Cats. Let them know it is from a Mustang and the two front are pre-cats. The Pre-Cats can often fetch more so let the place know what they are.
I also like THIS kit better because the cats are not welded on and it has very nice tips.
To finish this out right you should think about getting a GT rear bumper because it has the dual cut outs. You do not have to do this right away but it would look best if you did.
And in the end, even with a new bumper, your still cheaper than the shop and get get a nicer, throatier exhaust, more power and possibly a little better fuel economy depending on how you drive.
Lets not forget that if you do turn around and sell the car, you actually increased the value of your Mustang by giving it True Dual Exhaust.