I only have one drive in my unit and never plan on upgrading, so size doesn't matter too much and I prefer quality over bulkiness. I can personally build my own RCA jack with op-amp and filters, but the Hijack programming is not my forte either. So, if one was able to bring both the hardware and Hijack to the table, I'd gladly pay $100 USD.

Features I want:
24dB/ oct. and 12dB/oct lowpass crossover (selectable), gain, 180 degree phase switching via Hijack (more preferrably, fully variable or semi-variable phase adjust), and it would be very nice to have a coule bands of fully parametric EQ like the front and rear already have (I'd pay ya extra for that if necessary).

My stereo system is the most important thing for my car.

Jonathan