If you stay N/A, chances are you won't need bigger injectors. The 19lbers will support 350hp or so. If you go all out with the engine. IE Holley intake, custom grind, and TW heads, then you'll need the 24ers. Upgrading to new injectors is a good idea if they have many miles on them, just so you know the entire fuel system is functioning right.
You will need an adjustable fuel pressure regulator. Spending $200 for better injectors is a pittance compared to spending $4k for a new engine.
Go with the 70mm T/B if you go serious N/A. The guys making the big power are running them, and that's who I'd trust to have the combo's right.
If you stick to a Cobra intake, and heads that flow 220cfm or so, keep the 65. JMHO.