Being the noob here I hate to disagree, but every source I've seen shows around 11 seconds 0-60.

http://www.peachparts.com/shopforum/diesel-discussion/370804-1987-300d-12-seconds-0-60-what-else-check.html

http://www.peachparts.com/shopforum/diesel-discussion/390540-87-300d-0-60-time.html

If you've got a way to get it to 6 sec please let me know!

Regardless, thanks for the tip on removing the heat shield and the like, I'll make sure to do that before I start fiddling.