Salary Sacrifice

Hey there. I'm hoping to replace my car at some point this year and I'm roughly aware of the salary sacrifice scheme.

I was wondering what people's experiences with it are. Will it have a huge impact on pension? Can you pay off a chunk of the car in bulk? Is it massively expensive?

I'm a band 6 community nurse, hoping to push hours up to full time soon, to help. I'm torn between a new car on finance, or salary sacrifice. I just want a Toyota Aygo, so something smaller and not too flashy.