sully

Simplest tool for you would be postage and a box. Have who ever developed your tune flash your PCM. This is not something you want to get into if you have to ask this question.

Did you want a front mount or rear mount turbo, check the compression ratio on your engine cause to be able to run more than a small boost (5-7psi) you will need lower compression. Ideally you would have about 8.5:1 and throw a good crank and some forged rods/pistons and you could throw down 15-20psi at it and have a fun streetable ride.

Don't know where you get your info from but I have a 6.0 and supercharger in my Tahoe and am lucky to get 13mpg, maybe 15 on the high side with mostly why miles. I would stick to a set of headers, cam and tune if you want reasonable mpg. There is a write up on ls1truck about a 100hp on a budget build that would be good to look into.

It sounds like you don't have enough storage, get a bigger air tank or add another one to the current set up. Just adding another tank will not help you build pressure faster but it will have more in reserve. Also a Viair 450c is good to 200psi, check the pressure in the tank to see where the regulator is set, you may have room to bump it up some. Stock electrical is fine with one Viair, even with two you are only pulling about 40 amps but check voltage with the compressor running and the engine at idle to see where you stand. Hope this helps you get started.

look into seafoam, it is know to smooth the idle of older engines. Unless you are doing the swap yourself an LQ4 or LQ9 6L with tranny will end up being at least $5k installed, can be cheaper if you don't rebuild them before you drop it in. I'm nearly $20k into a forged 408 with a maggy but I am paying a shop to do it, would have been more like $16k if I could have done it myself.

Get a donor car like a 5.0 mustang and put that into it. I helped a friend do a 5.0 swap into a mid 90's Ranger years ago and it was crazy fast when he was done.

I like Corsa, Gibson and Magnaflow, Flowmaster has too much in cabin drone and gets annoying after a while.

Look into that 4hp gain. It will be like the 20hp gain that air intakes claim: somewhere in the paperwork it will have a disclaimer that says custom efi tune required to make peak HP increase. This being said a good tuner can get more than 4hp out of a completely stock vehicle by changing fuel curves and timing, you can even do this yourself with a little research and EFI Live software. I have purchased TB Spacers in the past and have liked the look and the cool sound that they make when the air rushes thru them but they are a novelty item in the performance world. Like you said earlier, you've done it and it didn't make much of a difference. You like it cause it was red and it looks cool and all that really matters is you are happy with your investment. If you are still running stock exhaust you will see a big increase from the intake system once you get all that extra air moving thru the engine. When you are done look into a custom fuel map, it sounds expensive when you first look at it but you will bring all your mods together and get the HP gains you are expecting once it is seeing the right A/F and ignition timing.

You wont see much performance upgrade on just an intake and exhaust on that 4.6L. Don't get me wrong it will help it breathe but not much actual HP gains. For the money a mild cam, air intake and short tube headers would wake that engine up. VA Beach? I'm guessing Navy, where are you deployed to? I'm in Afghanistan, Army.

Getting a job with the VA at your age is great, stick with it and you will have a rewarding career.