Got it cheap. What's the difference in cost going full dual to it or a quick simple 1 into 2?

 

Depends on what the shop charges, asking for rates on a forum is retarded as every area is different. A shop might charge you 5-600 to run the pipes and fit them, whereas another shop might charge more or less. Heck that number i made up. So go get an an estimate and if you're okay with it give them the go ahead to do it.