Replacing speakers in E46 BMW 325

Hey all,

I want to replace the speakers in my BM, the front are 6.5" so I was going to start there.

I am new to this so what would you recommend? I would like some good sound but also with some good punchy bass as well, I have had a sub in the past so not fussed about having insane bass but I have heard on other sites that I may lose the amount of bass that is already there if I replace them which I don't really want to do.

Also I don't really want to use an amp although I do have a spare one if needed.

I see a lot of things like coaxial, 2 way, component etc which I don't really understand, I also don't want to spend lots of money just have a slightly better, crisper sound with still some good punchy bass.

Would something like this be good:

http://www.halfords.com/technology/car-audio/car-speakers/alpine-6-5-coaxial-2-way-blue-titanium-speakers

Would I need an amp for these? Would the sound be what I would be looking for?

Thanks