when its just me in the car, she drives almost perfectly, but when my dad gets in, hes a bit heavier, she gets all tuggy and unstable, especially at motorway speeds... could this be something to do with camber?

Having a passenger in a BEC makes a huge difference, when I corner weighted mine just leaning forward in the driving seat moved 5kg towards the o/s front wheel.

I set mine up for one person, then found on the track, mostly right hand bends I was quicker cranking up the O/S springs a turn on the front and two on the rear.

You really need to set up on how it will be driven, adding a 12 passenger will really throw things.

Regards Mark

[Edited on 29/3/09 by mark chandler]