Besides the whipped texture, is formula any different from the standard St Tropez express mousse?

Yes it is! This product actually FULLY develops in three hours and has a stunning guide colour! The regular Express Mousse can be worn for 1-2-3 hours depending on depth of tan you want, but takes 8 - 24 hours to fully develop. The scent is different (a light soft floral) and I find the guide colour blends more easily too!