Instead of listening to a salesperson regarding RV's, I'd rather pay attention to a finance company; when you lease a car the cost of any option which does not add any money to a cars RV will be calculated as: cost/term.
So, as rough rule of thumb, £30/month per £1,000 of options on a 3 year lease.
On many cars where options like leather and nav are almost expected (so not on a Kia) those options will cost substantially less than that, meaning the costs are partially recoverable for the finance company through an enhanced RV.
Gone but not forgotten:
325i M Sport (E92), Black Sapphire, Coral Red Dakota, 19" 225's, Seat Heating, 6FL and de-badge
Replaced by 6.2 litres of AMG powered C class.