Unless you get a tune, run the 87 octane, others will not help and could hurt.
Swap out the AL104 for the AR103 gapped at .55 to .60 this will increase HP 3 to 5 more
Bottom end stock from what I have seen is ok up to 220ish If I remember right...
Auto tranny is a tank with stock HP, Even up to 180ish hp like I run, But more then that your wearing out the tranny at a high rate. I would never go higher then 200 HP on the stock tranny.. OBX headers are cheap and work well and can get them on eBay and the cosworth knockoff intake on ebay is good deal for $350 with some hand polishing of the ports.. or spend the $800 for the real deal lol
Car #1 2007 Focus ZX3 SE - Blue 2.3L, Automatic, Toms Tune, OBX headers, FSWERKS Cold Air Intake and Exaust, Loaded
Car #2 2007 Focus ZX3 S - Silver 2.0L, Manual,TOTALED!!!! (Half Rebuilt)
Car#3 Mustang GT 2007 LOADED!