Keen to put a system is the stock vy ss...

I have 4 pioneer 6" 4 ways and an alpine pdx-1.600 I am salvaging from my old car(written off while parked courtesy of my cnt neighbours). I am feeling 2 alpine SWR-1242D this time round and will get another pdx amp and have an amp for each sub (really good amps if anyone is interested) and will throw em in a ported custom kenel so they bark hard and will have plenty of power.

I dont think I'll bother amping the 4 ways but I want a dash/steering control friendly audio/visual headunit. I have read about a CAT-10 or something to make the steering controls usable with an aftermarket unit, Where can I find one of these and are there any exceptions?

Any opinions or info appreciated cheers.