A better speaker will sound better. Your best value and sound will be going to parts express (or similar) and buying your own. There's some work involved and you will have to make sure you have the right impedance and clearance so you are buying value getting a kit. I'm picky, so I roll my own. If you don't have time or want to mess around, buy the kit.

Edit: I just realized you were talking about pinsound vs pinball pro. My bad.

They are definitely better. If you have a PinSound, get the PinSound speakers. They are very (very!) high quality and sound amazing with a good PinSound mix (not all games have a good mix!)

Not to say pinball pro speakers are bad, but the PinSound speakers are made specifically to go HQ

You can dial in bass on PinSound, so it's sort of a moot question. PinSound + PinSound Speakers is far better than Stock WPC sound board + Pinball Pro speakers

Yes big improvement.be sure you also get the stereo cable ; I think it comes with the speakers. Stereo cable is a necessary component

Good job, my friend, you will not regret it! The woofer is very HQ, so you can dial up the bass a bit (sounds best if you cut a larger hole in the cabinet but it's not strictly necessary)

Something is set up wrong, double check your connections. The cab speaker should be super loud.

Also check that your treble / bass settings are correct. Put them in the middle, at 12 o'clock to start

What volume is your game set at?