Well, I could have a pissing match about how I have seen Si's run 14.6-14.9 w/ just i/h/e ( you gotta drive it like you hate it) and have yet to see an LS coupe run barely a mid 15.
As far as the B16A w/ an LS tranny, I can see how that would upset the engine, you gotta put a close ratio tranny on that engine, now don't say, well ,just but an S1 or S21 tranny on a B18B and it'll be just as fast, your right, it might be just as fast w/ a tranny swap but as long as you don't want to go any faster than 108 mph thats a good idea, plus on the highway you'd get owned by ANY other car from a roll because your car would run out of gears due to the low redline of an LS. I just have never had an LS beat me when I race my B16A Teg. Although, in my hatch when I had an LS and a GSR tranny I beat a 6G coupe w/ a GSR engine and a lot of mods, I think he just sucked at driving though.