I have the B&M kit in my th350, I went with the heavy duty placement rather than the street strip since my car is heavy. Installation was easy peasy. Took longer to get the trans out of the car than it did to install the kit.
Not sure about the transgo but they sound reputable. You'll love the way the car drives. Much better overall performance and I imagine better transient response with boost = less lag = more smiles per gallon.
