Since no one has replied I'll give my opinion.

As long as the EGR valve remains closed then you will have no drivability problems. If it opens at idle the engine will stall as it is a large vacuum leak.

The EGR is used to reduce emissions by lowering combustion temperatures and it's only used at open throttle. It has little if any effect on performance. If you don't feel a change then there is probably none. Some believe if you remove it you'll get more power. The leaking exhaust may reduce some back pressure in the exhaust and that might change performance.

I'd be a little concerned about fumes in the cabin so you should fix it ASAP.