Have you looked through the tuner threads discussing the differences between the two? Cause that's essentially what you're asking for and there's tons of information on it.
Here's one thread that came up when I did a quick search: http://www.ramforumz.com/showthread....ighlight=Bully
The overall consensus is that Bully Dog has better canned tunes (the preset tunes that come loaded on the unit) and the Trinity has the ability to custom tune. If you don't want to mess around with custom tunes then the Bully Dog is a better option. If you want to work with hemifever or whitelightning custom tunes then the Trinity would be better.
Based on the mods you have (if you don't plan on doing much more) I'd say the Bully Dog canned tunes would suit your truck nicely.
And just for the record.... your TB spacer isn't doing anything for your truck. It's essentially a whistle, that's it.