Bigger box? Different subs? more port? More power? Looking for idea

[JPinUSMC]

I have 2 15" Memphis Mojo motors/baskets with PSI soft parts in a box that is 35" x 27" x 16" external dimensions. They are at 1 ohm on a MTX 4001d. Tuned around 35hz. Doing 146.7 on the meter now, however I have done 147.9 on termlab with 1 15 before they were rebuilt.

Questions:

1. Do I need more box to get more numbers? I can build above the back seat, but I still want the back seat to go up into position. If I go that route the subs would then need to face forward/port forward. Suggestions?

2. Different subs maybe? I've though of trading them for a single 15 that can handle the power of the 4001d and building a bigger box. Thoughts? If I trade them, what do you think they might be worth?

3. More port? This is only going to change the tuning, so I dont think that is where I want to go with this.

4. More power? I have a single run of 0ga and the big 3 done with a large (85lb) former solar panel battery in the back with short runs off of it to the amp. Maybe dual imputs? I dont really want to spend the $$ on an aftermarket alt right now.

My endstate is to get some more numbers without spending tons of money. Any and all suggestions are welcome, but please provide an explaination as well.

[420c]

If its just for spl I read larger box ,big port area and higher tuning is the way to go. You can also look at your bracing and baffles to stiffen your box and try different port locations. its good to know your cars reasonant fs too to work with the tunning of your box for numbers.

[john253a]

Looks to me like you have a tone more space in that trunk and about 2" more height

Tunning higher will increase your numbers but will also decrease low end response

If you like you low notes then 35hz would be the highest you want to tune

If your a rock/country or anything else 37-42 is the a place to tune

And I'm getting 7.x gross of your box

So idd be saying your def on the small side of where you want to be