I love it, everybody says, "I don't care about the ride." Then their back in a few months complaining about their suspension.
before answering what upgrade you should do, I will ask what springs are you running now?
Overall both Eibach & Progress make wonderful suspension parts. If I were investing into a true coilover setup it would have to have adjustable dampening. Adjustable ride height on a street car is overkill & 90% of the people out there don't even know how to set it up properly and each time the ride height is changed the setup & alignment must be changed.