First, great write up.
However, you refered to the "L" model. DOn't forget about us poor Brighton folks. I assume they're the same bumper beams, eh?
Now, what are you talking about with cutting the stock beam to make it work? Obviously, you didn't do that. Do you know how though? Also, that sounds like trouble. THe beam is there for a reason. Cutting it would weaken it, no? Any idea on the strength of the STi vs stock beam? I'm thinking I'll take the extra 25 pounds, and pay the extra $$, and know in a head on collision, I'm not going to have a car in my lap. You think?