For bracket racing you'll want the auto... For street racing (ahem) I mean cruising you'll want the 6 speed... All things equal (ie rear gear) you will have slightly better accelaration and significantly better cruise rpm and mpg not to mention it's more fun to drive a stick... When it comes to consistency on the strip an auto is hard to beat... Or a Lenco or similar clutchless manual....

Hope this helps...

-Chris