If you do need to get a new unit, you can buy the same aftermerket EGR valve for under $50 on ebay! Even 40% off coupon from Advance Auto can't touch that price!

There is no performance loss when you disable EGR (or if it stops working on its own). As EGR only engages at partial throttle, when you are crusing at constant speed. Some people claim that it gives you 5-10% improvement in gas mileage, but I do not buy it… Did I mention that I hate everything about EGR system?