OK Guys,
This is one for the books.
I too have a HL Tiger, just completed a upgrade. I installed new metal gears and lubed the gear boxes.
I didn't have any of the internal electronics that worked. (Someones botched upgrade attempt sold on Ebay as something it wasn't, this is not a complaint just FYI) I installed a new ESC (ANT150) and started testing. Mine too has a tendency to pull to the Left both with plastic and the Metal track sets.
Its not bad just an annoyance.
Bullyhys