I think the Focus can be one of the better 2nd tier cars in STS.
In 2005 either Bart H's AE86 or my Focus were generally the fastest of the non SpecCivics; that year Jimmy C. was 7th at Nationals...the year before MKE had 4 STS trophies. Still, we were always at least 2 seconds off of the fastest local STS guys.
From what it looks like, your car and mine (old one) should end up being set up similarly...except that you have the 24mm FSB as well. JohnB on FJ has those, but he runs the Steeda springs instead of the H&Rs. He also has the LCR camber plates and speaks very favorabally of them.
Honestly, I think a Focus in STX would do even better...the LSD and the 8" wheel allowance (did you see Aaron W's new 15x8 ATS's??? ...they work on SVT brakes!!!) would put you closer to the WRXs and Bimmers than the Civics in STS (and the top STS (Jason F) and STX (Chris F) raw times are very close here). Had I kept mine, I'd have gone with a Quaife or Torson, etc...and tried my luck there.