I ended up going to Sycamore for all my service that I could. I had no dealings with sale there though.

 

I bought my EVO at Libertyville Mitsubishi, and when I went to get an oil change, I had an aftermarket BOV, intake, and intercooler piping. The service writer said to be careful could I could void my warranty, but she didn't seem to care too much about my mods. I just got my oil changed again a few weeks ago and since then added a cat-back exhaust and they didn't say anything. I plan on adding cams to my car, so I'm sure the next visit won't be so inviting. Who knows, maybe they won't be able to figure out that I added aftermarket cams if I get it tuned properly and it idles like stock

 

I've taken my Evo to Schaumburg Mitsu and they are pretty good about the mods. My passenger side HID Ballast blew out and when I took my car in to get it replaced, they didn't say anything and I have an Intake, Forged Recirc, Hallman MBC mounted in a very obvious place, downpipe, highflow cat, perrin catback, and samco ic hoses. What was very cool of them was, they even fixed all the recalls at the same time. So far, I've been very comfortable in bringing my car to them for Warranty work. I hope this eases some of your concerns .