I have a colorado w/ a 5spd. The trannies are pretty stout, but the other problem is that it would still require tunnel mods w/ regard to the crossmember.
Really the cheapest and easiest is the factory A833OD if you want an overdrive. If it is already a 4 speed car, it is by far the cheapest and easiest, and doesn't require any crossmember mods.
I have been running an A833OD with a 2.71 rear gear and it really isn't too bad, but I've got a high torque 360, too. Run a 3.55 and you will be more than pleased.
Is it the best? No. Are there better options? Not for the money.