Just had our Z3 resprayed due to the gelcoat coming off. West Highland Garage in Dunoon did a superb job. The guy has just started up. Colour change from Hellrot to Siennarot.
Lovely. I'm not sure what it is but when i look at some sienna reds for sale the look for more peach or 'pinked' than red. Not sure if this is paint fade or the metallic tricks of the light. Yours certainly looks the metallic red that looks lush and deep red.Can't disagree with your colour choice
Here's mine at the Bridge of Allan Car Show ==>