I'd put my money on the MM system. It is completly different from the stock setup. The Steeda system is just the stock 4 link setup with better controll arms and a panhard bar.
There's a little more to the Steeda setup than that. While it is simply a modified version of the stock parts, it is a more complete system than the MM is for only $1000. On that thought, I don't think I've ever seen a complete Steeda five link sell that cheap, but regardless- you will need to spend a lot more than that to get a MM suspension to be comparable to a stage three Steeda. Don't get me wrong- I hate Steeda as a matter of principle and I have a full MM suspension that I love. I would definately recommend MM over Steeda any day of the week, as I have in the past and will continue to do so. However, $1000 isn't going to cut it. A torque arm package doesn't even give you everything you need to make it work- you will then have to add the correct spring rates front and rear to make it work, which is another chunk of change. The torque arm works based on the principles of wheel rates- which are a combination of the dampners and the spring rates, and the weight at each corner. So, you will be wanting new shocks and struts too. The T/A rear grip package is a great place to start, and it gets my vote too; just don't go putting it in and think you're done. You won't be able to run against a complete Steeda unless you have a complete MM- or the other driver really sucks...