One old way to check is to push down on the front fender. If your shocks are ok it should push up once. If bad it will bounce a few times. As far as what shocks are the best it all comes down to how you drive your car. If you like to get on it high pressure gas shocks will give you a firmer ride. Low pressure will give you a nice smooth ride for KYB shocks come in both high pressure and low pressure types