Re: hoping to modify..
If you make your own diffuser (see the homemade/DIY section), it would help w/ splashing, noise and only alittle enhancement on the smoke taste.
I would highly suggest either a MYA Wide hose, Nammor or Razan hose. They should all fit into the stem and would help the draw considerably.
Also, perhaps consider purchasing a new bowl as well - I like MYA bowls, but I like my Eypgtian bowls better. IMO, the heat managemet seems easier, but it could just be me. Many will point you inthe direction of a Phunnel or Super Chief - as long as you stay w/ Med or Small, both would work well w/ you QT (look funny - such a HUGE bowl on a small hookah, but it does work). Phunnels/Super Chiefs have a different design that holds the tobacco in it's juices, making the smoke more flavorful and last longer.