rkduff99, when I was researching the lift for my truck (keep in mind that this was 10 years ago), I looked at the Trailmaster kit (back then it was only a 4" lift) but I quickly ruled that lift out even though it was significantly cheaper. That was the problem (atleast back then). They used inferior materials in their kits. Specifically, where the Fabtech and Rancho kits I looked at were 1/4" plate steel welded together to make everything, the Trailmaster kit was basically 1/8" plate bent to shape. While I am sure it would have worked for a street machine, that is not what I was building at the time and I am sure I would have tweaked that setup in a heartbeat.
I would ask to see if the shop can get one in (or if they have one in their shop) and to let you look at the kit. If you see a lot of 1/8" plate, save up your money and get a real lift kit unless all you are planning on doing is driving around on the streets. If the Trailmaster kit has 1/4" plate now, then by all means get it and it will probably do what you are after and be able to take a little bit of play.
I do not mean to put this kit down, but I am only going off of what I saw and my reasons for not buying the kit when I had it in my hands.