which dealership are you going to ?
I went to walsall, and they did a top Job.
Robin, (the owner) came up from down south to supervise, and I was blown away with price, quality, and sound. I went for twin exit, the advantage with the Zt is that you can get heatshields for both sides, I had to fit another RHS to the LHS, but you cannot tell.
if you drop me a PM with your email address I will post you some Hi res pics of my ZS with the twin exhausts fitted, suffice to say i had a lump in my throat when I picked the car up, it was such a good job !