We tested using the convertible, EcoBoost Mustang. At first glance it might not look like you can – the anchor points get hidden when the roof is down. However, the back is surprisginly roomy for a sports car and the front seats have a lot of forward/back motion options.
While it looks like a kerfuffle to install and extract the seats (and kids) without having the roof down, the long travel of the front seats means its easy to install the seat and capsule - and strap kids in - even when the roof is up.