Subwoofer beginner question?

If I'am looking to have more pressurization in the room, yet do not need any more more volume......would a sub with a larger driver help?
IME, yes.
Yes, try a 15-18" sub.....or more subs.

Yes but makes sure it is low Q. Since most manufacturers do not publish this then simply go large sub sealed box - since ports resonate you should advoid them as it will add volume without the transient dynamic pressure you seek. (think of a port as smearing energy over time - it takes the back wave and adds it to the front wave of the next cycle)
As Shadorne touches on, subwoofers are quite difficult to integrate into a system. If at all possible, I would buy used or get to try new ones in your system.
If a 12" sub is measuring the same frequency response in a room as a 15" sub, how would the bigger one "pressurize" the room better?
Haven't gotten to play with it but everything i have read suggests that you may have an easier time accomplishing your goals with two subs due to the flexibility in placement relative to the room

you can search here, Asylum and Google there is quite a bit
I used to have two first generation Sunfire subs; first the ten inch, then I got the twelve inch. The twelve definitely pressured the room way more than did the ten. But low and behold, when I used both at the same time, the two together complimented each other so well; each filling in what the other lacked. Namely, the larger subs' lower octave, and the smaller subs' speed. Now I understand why JL Audio developed the Gotham sub with two drivers! Why didn't I think of that?!
Thanks alot everyone! My room is 11x17 with the standard 8 foot ceilings. Have recently purchased a used rel q108 and really caught on how to dial this little wonder of a sub into the system, only I'am left with an itch for just a little more "pressure". This is the best I know how to describe it. Not much on measurements, just like to trust the ears. Was considering trying to find another one, as suggested, yet I'am unsure if it is possible to connect two of the neutrik speakon to the one amp. Have a YBA integre which the sub is connected to via the speaker posts. Anyone with experience? My curiosity is if this is not possible, what kind of change would come along if the 8" (q108) was replaced with a 10"(strata 3). Both are sealed closure. Having fun now........