Two 12" RL-P's Vs. Three 8" RL-I's

[MJ-tC 10+ year member]

How may RL-i8s would it take to match 1 RL-p12 ?. Would 2 do it or would you need 3. I have a RL-p 12 and that sub sound great of 800wrms ported at 32hz. But I want to get some room back in my car so I going with the 8s myself.