I had the pro kit on stock shocks and struts and it was a little bit more harsh over bumps vs my current stock sport suspension. It was a very nice ride overall though. People who rode in it didn't know it was lowered until I told them. I prefer the stance of the pro lot but the ride of the stock sport suspension a little tiny bit more. Install depends on your area but probably $200ish for labor. So you may want to just get matching shocks/struts while you're in there. That is probably the route I'm going this time.
2010 335i AW e90 Msport