Help..car just died..

Buy 2 ballast resistors Ian, like someone else said have a spare in the glovebox...they go without warning. Also carry a spare socket in glove box to change the ballast, not much sense in having the spare part and not being able to put it on. Same with coils they go as well without warning I think anyway, so if you can afford it, grab a spare coil and throw it in the car too.
One question for whoever knows, what is the difference in the 4 post ballast, versus the 2 post ballast??
Thanks
Steve