No mods, bolts right up, come with 2 new gaskets. I don't know about custom colors, that you would have to talk to Richard about. No drop in boost, seems to have stayed the same. I just put it on so I cannot tell you about any mileage changes. EGT's seem to be the same could be a little lower, since they fluctuate with driving/fueling not sure how you would really tell a difference. Go pedal seemed to have a little more response.
It does resemble the Swanker, but since the Swanker never got off it's feet and into production, as I see it there was/is demand, Richard rose to the demand and got it on the market. There are a lot of products out there that resemble other products, many are of better quality, some lesser. This intake horn is excellent quality, Richard put some thought into it to get it right.
CD