The 190E has some modest limitations which can be overcome with some careful planning. The 4" fronts in the dash are pretty much the max, so the Kappas are an excellent choice. Just break off the mounting tabs, use some silicone sealer and then press fit the drivers. You should use bass blockers to prevent that little driver from seeing any bass, or just use the crossover that Infinity uses if you're sure you're not going to jack the amp up. There is room in the lower kick panels and the doors for 5.25" with some careful cutting.
One weak link in the stock system is the console front/rear fader. You'll have to decide if you're going to keep it or bypass (pull a few new speaker wires to the HU) it and use the HU's fader.
The rear deck can take 6x9 with little to no cutting depending on the magnet size and the height of the grill mounting. 6.5" rounds fit with no cutting. For bass, the usual method is to remove the first aid box, cover the opening with a grill or speaker cloth and use an enclosure in the trunk, with insulation to keep the tail lights and vents from rattling.

As a 190 owner, check out 190 Rev
for maintenance, upgrades, and tuning of the W201!