Upgrading sub to get a live feel.

Clio09, any 911 can be a valuable car as long as it has not been wreck, is not rusting and has not been modified. You want to use the factory mounting points for speakers and electronics that fit in the factory space. Outboard woofer enclosures are fine. No cutting or drilling metal! If the car is a renegade then the sky is the limit.

Excuse me for the last post. I'm on some pretty heavy drugs right now and my mind is stuttering. The tie rods and struts can always be returned to stock. When was the last engine rebuild? You can always make it a looker again if you put the money into it but for a fun driver you just have to keep up with the basic stuff. 911s from 78 on are all galvanized so you really don't have to worry about the paint that much. It is just an aesthetic thing. The external rubber parts can get pretty moldy if the car was parked in the sun. They are easy to replace with modern rubber. Good that you have an indie you can trust. Not easy to find. Thing about 911s is you can make them go forever:) 

@mijostyn, what engine rebuild, lol, 208k miles (112k with me) and not even a recommendation of a valve job on the horizon (has had a transmission rebuild though). The clear coat is flaking off the trunk lid due to some foreign substance that dripped on it while I had it parked at SFO during a business trip, but other than that I just need to wash it more, lol. Interior is very presentable other than the typical dash cracks and the AC stopped working years ago. Don't really need it around here though. Most techs rave about the 3.2L engines as being among the best Porsche ever made (my tech has a car out there with 450k and one valve job on it). Sure the '68-'73 series looked sexier, but the '84-'89 series cars were always being recommended to me when I looked for a replacement for my '72 Targa.

lol, this thread is way off topic now, but I got my subs so lets play.

I listen on average between 90-95db.

The PB-1000 is significantly larger in size than the SB-1000.

The room size is 16x30. The speakers are placed on the 16 side, and I sit about 11 feet away from the speakers. The SB are located right under the main,  6" from the wall.

The SB-1000 are set to about 65Hz to blend, zero phase, 60% volume. I’ve always found very clean and articulate bass at this current settings, and anytime I’ve made an adjustment, I’ve dialed it back to these.

First test just running one additional sub (3), placed on the left side besides my seat, set at 60Hz, played with gain to peak bass, and 60% volume. The biggest difference is an increased amount of headroom, the speakers felt slightly larger. It blends well in this position, but you can feel the physical bass being directional. That feeling makes you slightly detract from listening.

Second test, quad sub, placed along side seating position against the wall. Similar settings, but with 45% volume, because the wall gives it a boost. I get a nice spacial balance, but I could not get them to blend in this position. At those settings, I got a bit of harshness in the low regions.

I finish the evening with using one additional sub, as I got tired, and just wanted to listen to music.

I think I have to lower the crossover point when running dual tonight, and see how that goes. 

Have you tried a more asymmetrical positioning with the two extra subs. IOW place a couple behind your speakers along the front wall, then the other two should be place along the side walls, but not symmetrical, stagger them. I have also seen arrangements recommended where the subs are place along the front and back wall. I think someone may have linked to the article in this thread. You also have the challenge of setting the volume level of the subs optimally. There are better experts on this thread than I to advise on that. Keep playing with it though, you will eventually getting it dialed in.