[GretchenGotGrowl]

At this point there is no supercharger kit for the LLT. STS makes a single turbo kit and two companies are working on twin turbo kits (SC2050 and IPS). All of these options will get you beyond the RWHP of the SS with the LS3, but they aren't cheap when compared to the Long-Tube headers. If you go with the headers, then you will have to consider what that means for future mods. If you want to later go turbos, then then you will either have to toss the LTs or go with STS.

Anytime you go with FI you will reduce the longivity of the engine. However, if you use good synthetic oils and change them frequently it probably won't be enough that you will notice. Let's say this engine in stock form is good for 200K miles before a rebuild. With FI, resonable boost (say 6-8 psi), changing oil every 3K miles, tranny and differential every 9K, then you will probably still get 150-160K miles out of it. If you frequently trade in vehicles, then you probably won't notice that. If you plan to keep it and keep improving the performance, then you will probably put forged internals in long before 150K. That's my $0.02.