My .02 on the STB. I installed the Steeda and it's probably the only thng I regret doing. Although it made a difference on my vert there are a couple reasons for NOT doing it.
1. It's kind of a PITA to install. Seems simple but it does take some time to line everything up, tap the holes, cut the plastic at the firewall, etc.
2. The Steeda does not clear the Mac CAI I have, so the tube from the MAF to TB had to be modified a bit.
3. Where it attaches to the firewall is pretty thin - I fabricated a brace for behind the firewall to strengthen it.
4. If you don't use threadlocker on ALL of the bolts it will come loose.
5. Probably most importantly, if you plan on doing any other mods or engine work it gets in the way. I've got cams waiting and it will definitely have to come out for the cam swap. Just a pain.
Just some input from someone who's installed one.
Jay