Current Kappa will work well and drop into the factory holes (take the tweeter grill off carefully and it will drop in as well).

The current and new to come kappa models feature Infinitys "true 4 ohm technology" which really means it is better suited for a 2 ohm application such as in our cars. It starts at just around two ohms but as you use the system the impedance rises close to 4 ohms, normal 4 ohm drivers can rise past 6 ohms dc.

The amp has some eq, limiters, dsp in it, but from my own use you will be ok.