Any Aero or Plus 8 owners with rear exhausts, do you get a toxic smell wafting into the cabin when you're roof down and you accelerate?

Trying to figure out what is causing it on my Plus 8, the suggestion is that it's the exhaust boxes (non Morgan, non Librands).

My S1 Aero certainly didn't smell like this... it's like a burning plastic smell rather than oil or fuel.

Thanks.


Current - 2013 Plus 8
Previous - 2002 Aero 8 S1, chassis number 96 - Ragusa Green Metallic