Superchip.
Because it raised & firms up the ATX shift points. That alone is worth it! Also it tweaks the spark curve, fuel enrichment, IMRC point, redline, and speed limiter as well.
Custom mandrel single exhaust is a big plus - I would go 2.5"
Larger MAF - probably not worth it without more extensive intake & exhaust mods.
Larger TB - see above
