Just so you know, the '08 and up 5.7L Hemi is a more powerful version (+10 hp) with Eagle heads and a better intake manifold. The '06 and '07 engines also had a few issues with dropped valve seats on a small number of engines (manufacturing flaw) and the shifter interlock can break locking the car in park. The shifter design was changed in '08. Most of the earlier shifters were replaced under recall but there may still be some out there.
You can check the VIN on Dodge.com (owners tab) to see if there are any open recall services outstanding.