Livernois has a fairly good reputation. I have seen TEA's work, and it is second to none. Also BBR has been stepping up with the 3v heads for a while now, and I havn't heard anything bad about them. I would shy away from MMR, I've heard of too many issues with not only their heads, but everything they build. (lack of quality control)........Get with Richard with RADmustangs, he can get you some good deals!!
Its hard to beat the price of Livernois. added with the fact that it is a big company and if something goes wrong, they have the bank account to make it right. I broke a valve spring, i had a new one the next day.
Fox Lake is going to cost you more if you want upgraded valve springs.
BBR? no offense buy all i hear is talk? Iv'e yet to see a dyno or a track time on cams and heads backing up these bad ass claims. Like i said, no offense, maybe they are out there and i just havent seen them. But i would want to see something before i bought it. If you want in the game then get in the game, you cant just post up vids of Idling cars.