Got similar speakers in the front of mine component 6 1/2" KEF, they are Dynaudio made jobbies, Genesis used to do the same setup with their name on it around £300.
Will need extending out from the door like the originals so window clears the back. Available from decent shops or ebay like this http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... mot_widget
Got a Genesis Profile 2 to drive the rear Macrombe 6 1/2" but the main usage is from a Genesis SM110 driving the fronts passively with decent cable not the standard junk. Dont skimp on the RCA phono interconnect.
Have used Alpine for many years now got a D310 simple for normal use and when set up. All other head units will be as complicated as each other, slow down read the manual Alpine are the best for sound throughout the range.
Will need something like Alpine to Vectra wiring loom adapter i used Autoleads PC99-ALP Multistalk Patch lead £2.49 & PC99-X06 Multistlk adapter £19.99 Total delivered £28.98 next day. Now i have steering wheel functioning head unit 90% working ok. Alpine from £65 upwards.