[SVN] Plugin or Bundle?

[Wesley Smith]

Hi list,
I have an idea for using TextMate as a live coding interface and I'm
wondering if the project should be a bundle or plug-in.  I've been
poking around the documentation, but am not totally sure what's
possible.  Here's the idea:

I have some code that I'm writing in TextMate and want to evaluate it
in another application, which is already running and listening on a
port for any code that might come in to evaluate it.  When I press
Cmd+Enter, I want to be able to grab the currently selected text and
send it over to the application on the proper port with appropriate
message headers to that it's recognized as source code and evaluated
as such.

Ideally, the part of this that lives in TextMate should be running in
the background and I wouldn't have to relaunch it every time I press
Cmd+Enter, but I can live with running a command line executable to
send off the code if need be.

So, is it possible to even grab the highlighted text?  Is is possible
to pass to a command in a bundle?  Can this be done with a plug-in?
What are the pros and cons of bundles v. plugins?

thanks in advance,
wes