Funny thing to me is that everyone says the 4 doors are louder. I have no experience with a 4dr but I can do decent #s with my 2dr considering I can hit legal 150.3ish with only 1400watts of actual clamped power. That's using my 2 NightShade 15s in a side ported setup.
I'm not concerned at all with burp #s with this setup. My primary goal is a solid 149.9 BassRacer with around 4kwatts. I'll be testing out a pair of saz-2000s in here this week and hoping to hit my goal with them. No doubt it could burp much better if tuned higher. On paper tuning is 36hz but it plays solid down to 28hz. Just check out my YouTube vid playing V.I.C. - Get Silly which peaks @ 28hz.
It currently peaks @ 48hz on the TL. Typically peaks @ 53hz.