Ahh that sounds unusual of lee to do that to you.He use to be pretty good.fair enough if you and lee had came to a arangment to do it in stainless but one thing for you.depending on what type of wall thickness the stainless is, stainless seems to resonate a fair bit compared to mild steel, which can make your car sound drony, but also it varies on the type of muffler used.
i have just made my cat back exhaust myself back to mild steel, mandrel bent of course and i can notice the difference.Personally i wouldnt go stainless unless you plan to keep the car for donkeys years, but i would be annoyed if this happened to me if something had been agreed on.