This engine is a candidate for the Banks upgrade, as long as you have the Allison 3000 series transmission. Before you do anything to 'goose' up your engine HP and torque, check with Allison to make sure the transmission is rated for the increase in power and torque.
Banks would be my recommendation.
'07 Winnebago Journey 34H - CAT C7, Koni's, MCU's, SS Bell Crank, Safe-T-Plus
'07 HHR Toad, SMI AFO, Blue OX