We already have an I4 LTG Engine, Exhaust, and Bolt-ons section:
http://www.camaro6.com/forums/forumdisplay.php?f=234. Its right below its V6 & V8 counterparts.
There is also a Forced Induction section, which isn't tied to any specific engine or FI type. Turbo4, supercharged V8, nitrous V6 ... whatever.
And then there are the Member Car Journals, which exists so that members document & share their builds.
Lastly, in time I'm sure that the Dragstrip & Launch Techniques subforum will feature an I4 fast list along with the V6 & V8 lists there already (although the V6 fast list is currently empty on Camaro6).
I can't think of anything that anyone will be doing that wouldn't fit into at least a couple of those.