200sx models...

[FunkyNige]

I've been looking around at 200sx's for a while as a possibility for my next car, but I'm a bit confused about all the different models.
I've worked out it's the S14 I'm after, but I see there's the S14, S14a and Touring models, what's the difference between the three? Are there any other variants on the S14 I should be aware of?
I would ask on sxoc.com but I'm sure someone on here will know and it saves me registereing...