Bilstein HD's. You could go with a coilover kit also if you're pretty interested in autocross/redic handling! Maximum Motorsports has a great coilover kit/package for the Cobra w/IRS, I love mine! They also sell Bilstein shocks/struts, and if you go with their coilover kit and buy shocks/struts from them you won't have to worry about sending the rear shocks back in to have the required groove machined in.
If you don't want to go with coilovers, still stick with Bilsteins. They can be had on eBay for pretty good prices such as THESE.
Tokico is also another brand I've had great expirience with. Their Tokico HP's (known as "blues") are awesome for the price, and if you're wanting more adjustability for autocross their Illuminas are pretty good.