Couldn't love this enough. Congrats! And I'm with you: totally stunned these aren't more popular, you can get ones in great shape for less than $500 all day long and they blow away the new Ibby's that sell for 3-4x that much.
My 91 S540LTD is the best guitar I've ever owned. It was the same red as yours when I first got it, but now it's blue. I tried a Dimarzio SD in it when I first got it, but it didn't sound much different than the IBZUSA it came with, so I sold the SD and bought an Invader which sounded incredible in it. Then I got bored with that, yanked it and sold it and now I'm eye-balling a Black Winter for it. Do you know what model Dimarzio you have?