cool I just brought 2 x Logitech Z506 5.1 setups. Not sure yet if ill actually take out the seat speakers or just wire them up inplace of the actual Logitech rears. I cant remember what impedance the rears were but I believe they were 6 or 8 ohm and im pretty sure the Logitech speakers are 4 ohm but ill check it out. Im pretty sure you can use 6/8 ohm speakers on 4 ohm amp with no issues except lower overall volume, just cant use 4 ohm speakers on a 8 ohm amp etc
then ill have to do the same on the sega rally 2 cab which ive done a bit of work on in last couple weeks now