Before you purchase anything else talk to the professional about it. You don’t want to get mismatched items and then go through the hassle of returning things.
The Blaupunkt speakers are ok for starters and you’ll be fine I would suggest getting the matching 6x9 so it would be easier to match with a head unit and amplifier.
remember don’t fall for the expensive amps. As far as a head unit look into digital media receivers if you don’t plan on using any cd’s
This inline amplifier works with one of the alpine head units. Plug and play so you can do it yourself. Only issue is sometimes you might need to run the power directly off the battery and ground as well.