Diffuser getting 'sooted'

[Dr_Rick]

I have a 2014 Elise S with a Stage 3 exhaust. I've noticed that the diffuser either side of the single exhaust outlet is getting sooted up. Should this be something I get looked at? As far as consumption is concerned (I know it's all relative) I'm getting around 250-275 per 3/4 tank. I've had the car from new and it currently sits at just over 5000miles. It's due in on the 19th for some other bits, so wondered if I should add this to the list.

I'll get photos later in case it helps.

[Bebee]

Normal mate, I get it on the number plate too, TBH I like that used dirty look.