Theirs a guy here who had 3 Type ARGHHHHSS in a 98' Camaro..
3 Type R's sealled and metered a 141.5 and was like....WTF???
So I told him to remove the middle sub, build a port and come back and try it again...so he did...bam 144.9...
I'd say around 34-36Hz would be perfect....but it really depends on your listening preferences...