RS/GS models dont use a MAF, they use a MAP sensor. You'll need an FCD or a missing link to keep the MAP from seeing boost. 450's won't work without a resistor pack. 7PSI can be achieved with a 12:1 FMU on stock injectors, (Cheapest) but you'll need a Walbro 255HP model fuel pump. Also your injectors will be nearing 80-90% duty cycle with a 12:1 increase in pressure. An SFMU is more ideal, then you can utilize 450's with a resistor pack and run a little more boost. (Provided you're not using OEM internals.)

You'll need an oil feed / return setup. You'll need to weld a bung in to your oil pan for the return. You can tee off of the OPSU location for the feed.

Obviously things like a turbo manifold, BOV, boost gauge, aftermarket oil pressure gauge / sender, and EGT gauge (I cannot stress this one enough.) Wideband is always nice, but at 7PSI you can forego it if necessary. Unless you're planning on an SFMU and 450's; As it becomes necessary at that point.

An AFC is a moot point at that level; If you're going to tune it either go with Megasquirt or a PortFueler.