The placard is only good for STOCK tires (which we all know sucked to begin with). My BFG's I keep at 40+/-psi. You'll want to soften them up for sand, but for strictly street use, I'd lean torward listening to your mechanic. Then again, you could also look at the load ratings for your specific tires and figure it out from there...
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'03SE

BFG AT/KO
Custom fuse panels for electrical mods
Custom backup solution mod (lights/camera/monitor)
Custom switched power outlets (8+ total)
Lots-o-Lights (6 driving lights, 10 total)

Original registration - Sep, '03
Pre-crash post count - ~1100