pros of a stock one - it comes with the car.
most likely wont leak
matches your gauges.
cons of a stock one - they charge too much for it
- its not in psi
- looks cheap
- not as accurate as others
pros of aftermarket one - looks sweet
- more accurate
- in psi
- you can mount it anywhere you want
cons of an aftermarket one - might leak, but fixable
- you have to install it
- it takes time to go buy it and then install it.
hope that helps. i went with an autometer gauge and installed it a couple days ago. i love it. it looks sweet.
hope this helps