so many people post useless ****, he told you his goals, he wants 400 hp. The fastest way to get there is to spend money, and not on bolt on **** that will not help much.
ssms has whole engines you can purchase that bolt in, you would need to buy that engine + a new tranny and new rear end. these pre built engines come with superchargers and cost about 8grand and give like 600 hp im sure you could get less hp for less money aswell.
Essentially if you wana use your current engine youl want a new cam, Forged internals will help prevent blowing up your engine under boost (which you will need) I personally like superchargers rather than turbo's they give a better sound, same amount of power with less work and less potential to explode and look cooler IMO turbos are for ricers. You will want an 8.8 rear end which isnt very expensive or hard to install, you will need a new clutch and or transmission, clutch at minimum though. Back to the engine, you will want to port and polish your heads, you will need a bigger TB and bigger gas pump. Trivial items will be needed aswell, plugs/wires, probably a better exhaust unless yours is already a dual. Im sure im forgetting all kinds of stuff, but essentially you need to completly rebuild your engine and drivetrain and suspension.