The 30 Watt RMS Kicker would walk all over the 40 Watt peak head unit.
Picture shows 2 sets of RCA outputs on the back. The specs say 1 pair of outputs for rear. Maybe updated? If you have 2 sets of outs, Is the 2nd set for a sub, or for fronts?
If it is a front out, set the Input Level of the Kicker to Lo, If you are using the speaker outs of the head unit, set that to Hi.
If it only has 1 RCA output ( rear) I would consider using a couple simple "Y-cords" on the output, run both the Kicker and Blaupunkt off that, but still run the Kicker to the front speakers. Then get the 2 front speakers blended with the sub til it sounded good. Then add the rear speakers off the front output of the head unit as some fill. The clincher here would be that the Front/Rear Fader control on the head unit would be backwards. Other than operation, there's nothing wrong with that, it's just stereo, there's only 2 audio channels-Left and Right.
OR
Forego Fader control, run both front and rear speakers on the Kicker. Tweak the system with the gains (or Vol) on the amps, and the Crossover & Phase to get it as good as you can. Leave the Bas Boost set to zero on the Kicker. Try different musics and conditions until you get it "right".
Then, just use Volume, Balance, (L-R), Bass, & Treble on the head unit.