Maybe a pinched wire or short in the harness or something like that, given the wiper malfunction. Does sound like a dealer issue. Just to make sure it's not something simple, check your fuse box re: wiper malfunction.
Also if the boost gauge went in recently, check its wiring, for correct routing and integrity. When we intall stuff we sometimes accidentally disturb wiring that affects operation of other stuff. Even the intake install could have resulted in your accidentally pinching or otherwise damaging some wire. There can be crazy unexpected side effects.
But if all has been working well for some period of time and the CEL and wiper malfunctions are long after your mods, then it is probably time to let the dealer sort it out.
