Almost dead in my 2000..

As I pulled away from the toll booth and accelerated to
> about 60, the car to my left veered into my lane. The only thing that
> I could do was move to the right... really I just reacted and flicked
> it to the right...but as I did, suddenly my MX5 lost traction and the
> rear started to come around to the left and for a brief moment I was
> sliding sideways...

Let's see, you were rapidly accelerating, then some one cut you off.
You quickly flick to the right and probably let off the gas or even
hit the brake. All this weight shifting can cause the back and inside
tires to have less traction than usual. Add this to the rapid turn
and deceleration, it's easy to imagine your car losing traction. The
right thing to do would probably be either to quickly slow down or
quickly turn, but not both; there's not enough tire adhesion. This is
anti intuitive and I doubt I would have done better on a split seconds
notice.

However, your tires PSI may be a bit high. I keep mine around the low
to mid 30s. Not that I think this would have save you from a spin
out. Glad you're alright.