Yeah, it's kinda scary the stuff available for trucks that mostly just gouts fuel out the tail pipe as "black smoke". The unfortunate trend among those with the HD trucks isn't at all about power & economy but just show-n-go. If you're making "black smoke" you're not tuned for maximum power as that smoke is mostly unconsumed fuel. It's normal for heavy equipment and commercial trucks to do it to some degree when under heavy load as the engine is burning as much fuel as it can while getting up to speed, but not for a pickup truck trying to get a set of 26" hoops down to McDonalds.

For the VW TDI's there is quite an active tuning community and they're showing up in greater numbers at the drag strip, autocross and rally events. Diesel Geek is just one of many vendors with shiny new doo-dads to improve performance on these torquey little oil burners. I've got entirely too many projects and irons in the fire to start messing with the Jetta, but it will be SOOOO tempting when tire-time comes 'round! :bwgr: