How durable is the black finish? I now have a 2:1 system by another brand and any little rock I kick up scratches it and it turns into instant rust a day or two later. (i live in Daytona Beach FL). Also will it turn into this funky orange color after a month? Mine did every dealer I went to and a bike school (MMI) said it was the finish and my re jetting was correct. I just want to ask before I shell out another 600