I too am confused as to why you would use the text method, that's known for its slow push of updates. I used that when I first started using Twitter and would get my girlfriend's tweets up to 2 hours late. Then I got a Droid and used a dedicated app for it.
I use Seesmic on my Droid for twitter. I can set intervals in the settings for polling as little as 5 minutes, I believe. I can also have it send me notifications of new tweets. I follow a ton of people, so I turned this off... else I'd be getting notified every 30 minutes when I'm scheduled to pull. I only get notifications of DMs or Replies.
This way you dont recieve everyones new tweet....rather just the people u choose to recieve it from. You cant do that thru an app...only thru online which is what I've been saying here.
and it seems like at times theres a delay of when u recieve those tweets.
I don't use SMS for Twitter at all. Not on an unlimited txt plan, so I use my allotment carefully
Seesmic does offer the ability to create groupings and filters. I've not used them, but the ability is there. You can set certain people to certain groups, if I read correctly, and only have their tweets appear in the phone app.