Nice install!!!

I wanted to ask a couple of questions which I hope you may be able to answer!

I Can get Dynaudio speakers at a good price however I dont want to put amps and all the other stuff in my car, as BMW in the UK would invalidate my warranty.So if I just put the same speakers that you used will they fit easily,So old speakers could go back,and would I need to use any cross overs or would the standard BMW work and would I gain a much better sound ? I have DSP if that helps

Many thanks