for a 2011, its the 1.8l out of the cruze and astra. Cheap, bolts in uses the same wiring and maybe even the same ecu (interchange on ecu is "mixed" which is other good news). but can be done for as little as $1000 if you do it yourself. And its a easy 140hp. With a $300 trifecta chip, it should reach 150? hp.. if you also do the muffler, cai, and light weight pulley youll see more still. Thats @ $2000 for potentially 60 more hp.