Upgrading sub to get a live feel.

I would have stuck with sealed subs and got more of the SB 1000 or SB 2000.  Are you using the system for home theater also?

Should I have the seal or ported closer to me?

I watch a few movies here and there, maybe once a month. I don’t really care that much for movie sound quality, most of the time it isn’t master very well, at lease the ones I am watching. But when it does it’s nice.

I think you can always plugged the ported ones up and get close for testing. 

I'm not sure what the best answer to that question is.  My intuition is that it would be better to have the ported ones farther away in case there's port chuffing.  On the plus side, the PB 1000 will go lower and have more output than the SB 1000.  I suggest giving SVS a call and let them know how you plan to use them and get their advice. 

I am still concerned about him having enough output even with the addition of two PB1000s.  The PB1000s run out of steam at about 100db in the 20-30hz range.  Even if you combine them with the SB1000s, depending on how loud the JBL's are turned up, the subs are still going to run out of output capability.  All four, with being used in a distributed array are likely to max out in the 105db range at 20-30hz.  

https://referencehometheater.com/review/svs-pb-1000-subwoofer-review/

If staying within the SVS line, I would consider spending the extra for the PB-3000s.  This will get you the output that will keep up with your mains, plus 3 band parametric eqs to help with any final tweaking.  .  

Finally, I agree it is a good idea to discuss with SVS, making sure you have your room dimensions handy.  

I still don't think we know how big the room is or what the OP's budget is.  Adding two additional subs that have more output should be an improvement regardless of room size.  If the four subs don't have enough output and he can stretch his budget, the PB1000's can be exchanged for something bigger.  Let the poor guy aft least try out what he's bought first.