What kind of gears do you have? I put an OD 60A 5speed in my ute and it's a godsend. Even just around town (we've got lower speed limits than you guys) it's awesome, but that's with a stock ute diff and close to stock height tires (for a ute). Not sure about your setup. My wife's ute kills me with the revs so high.
Not to thread jack, but are the 240K (or earlier L series boxes) different than the R30 stumpy box? Sorry if I come across as "uneducated" in the matter.
The stock seat's are not too great... I put some R32 GTR seats in and they sit really low, plus they have really thin backs and provide maximum legroom. My buddy's like 6'2" 260lbs and can drive it. He had OEM recaros from a mitsubishi in his.
What i've found is .200 from V8 guys and .140 from a BMW guy, talking about accepted thickness on small, hi-po 4cyl engines. This sound about right to you guys?