Just a question. Could my '04 be "reprogramed" to put out 191 HP?

How does the 04 TB only have 191 advertised hp, should be 275?

Do you mean the 291 hp version of the 4.2 I6 in the 06? That can not easily be done. GM changed the ratings partially because of the new SAE standards - slightly different method of testing increased most newly tested american cars - notice how it is no longer rounded to the nearest 5 hp, but exactly to 291. They also made modifications to computer stuff and things in the engine.

Most of the modifications were internal, so the short answer is no.

You might, and I mean might be able to reprogram an 02 with 03 software to gain the extra 5hp/5tq, but the PCMs are different part numbers so I bet the programming wouldnt work even for that.