Rambling long rant mode on:
Get the AEM EMS P&P if you really think you need one. It's going to be the easiest to install and use. It you are hardcore into weight reduction then look into a Haltech, Autronic, Motec, SDS, etc. AEM makes a race non-p&p version, but it's quite spendy compared to the P&P versions. The AEM is the best bang for the buck in my opinion. Some people like the SDS for simplicity and price, but I can't see spending all that money on a standalone that can't datalog.
What in your setup is going to require a standalone? You can go a long way with just an AFC and right size injectors or with DSMLink on the 2Gs. The amount of time that it takes to get a standalone running like a factory ECU car isn't for everyone. Don't expect to pull a Dre and make 500whp on pump gas just because you have a standalone either. He has been working with the GEMS/Pro-EFI/AEM EMS systems for a good 3 years. He also likes to make it out like his car is 100% reliable and not tell about all the headgaskets he has been through, how his motor eats a quart of oil every 400 miles and how he can't do a 4th gear pull on that tune without destroying his spark plugs.
BTW, if you think so highly of tuning, you might want to learn how to spell it right. Tunning is a different real word and has nothing to do with tuning a car.
There are 2 things that are more important than tuning for a car to make good power:
1. It needs to have a combination of the right parts for the power. You might want to look beyond the cheapest parts or past the biggest name parts. For example, the throttle body flanges on the Dejon tool upper i/c pipe are just way too thin to trust for a good seal. And the Greddy FMIC is a decent setup but it's components are bit of a compromise. A 1G BOV is cheap and then can hold a fair amount of boost when crushed, but some of them can be faulty to begin with and leak no matter what you try to do. You have to make compromises too, if you want to make 500whp expect to have to run a laggy turbo. Even with all the advances lately with ball-bearing and GT wheels they will still be some lag. And if you do make a super high flowing compressor wheel spool quickly it will probably just surge anyways.
2. It needs to be installed correctly with an attention to the small details. The simple shit like checking for and fixing boost leaks using an air compressor not a bicycle pump can make a huge difference in power. It doesn't matter how efficient your turbo is if it's leaking 5 psi to the atmosphere.