Dash speakers aren't really a speaker type, more of a location.
The infinities are co-ax. They have a built in tweeter (which you can see in the middle of the cone). That's a tiny speaker attached to the big one. Then you have the main 5inch one. There'll be an inbuilt crossover set to make sure the little speaker (tweeter) receives freqs higher up the range and the bigger speaker (mid) receives a lower range.
Components, as mentioned above, have the tweeter and mid seperate along with a seperate crossover allowing you to install the speakers in seperate locations. For instance generally a tweeter works best on the a pillar as far forward as possible whilct the mid works well in the doors.
Allowing the speakers to be mounted in different locations allows for greater control of the sound they produce so you can tailor the sound to how you like it.
They're not that bad but not going to give you as good a sound as a set of components. Although buying a set of comps and throwing them in there probably aren't going to sound much better tbh.
I'm not sure of mk2s but you want the woofer to be installed on as solid mounting as possible. MDF usually
If I were you I'd look at experimenting with the ones you've got. Look at moving the speakers about to see if you can get them to sound any better. Try the doors for instance. Try making an mdf baffle for them to increase midbass response.