Danyal, contrary to a previous poster's claim the car is irrelevant. I now have an E46, I just moved from an E30, which was very, very similar to the E36 as far as the speakers are concerned.
The point is that the simpler you keep the system the better it will sound. Components will always sound better than coax because of the ability to experiment with the placement of the tweeters before you actually fasten them in place. The smallest movement of the tweeter can have an huge effect on the sound. In fact in my E30 I never fastened the tweeters permenantly in place, I just had them held with double sided tape and actually moved them every few months until I got it sounding "perfect".
El Pres. is correct about component speakers though, you get what you pay for. I like the Infinity Ref. components, although they are entry level they sound pretty good. Phoenix Gold Octane 5.0 is also a good sounding, easy to install set. They are better than the Infinities, but they cost a little more. Avoid the Alpine components unless you are going to get serious about the rest of the system.
Now these 3.5s, forget them. They are a waste of time and space and more importantly money. If you were going to spend $100 on a set of 5.25 components and then a further $50 on those 3.5"s don't. Spend the full $150 on the 5.25s That extra $50 puts you into the next league, especially where sound quality is concerned.