educate me please

A turbo/s, 255 in-tank, AFPR, and injectors will get you 400RWHP on a stock motor(with a tune and chip of course). The AOD will probably grenade in short order, but so would a T5. Try a C4, Tremec, or Lentech to back up that power. To max out the stock block, add heads and intake to the mix. After 450RWHP, its a crap shoot on whether the block will live or not. Dont bother buying a cam, the stocker will make more power than the block can handle and do it with a smooth idle.

AC

You can put down healthy 300's with nothing more than a healthy stock longblock and a good supercharger.

The aod won't last for **** even in a stock mustang, and will slow you down by a full second. Swap out to a t5 (which will still grenade, but not as fast, and is almost a second quicker) or a tremec which is nearly bullitproof, or build the aod. To make the aod much better, and stronger, you'll need a good torque converter, solid one piece input shaft, trans cooler, shift kit, and a manual valvebody.

As for the engine, Like mentioned, a good supercharger will get you mid 300's without a problem. If you want more, make sure you have a healthy bottom end, swap in a cam, some good heads, an intake, then a supercharger. That should provide a very reliable 400+ horsepower setup without going to extreme.

you could also consider going naturally aspirated. Get a 347 stroker with a good cam and heads, and you'll easily be putting out high 300's. those horspower ratings are not difficult with 5L engine