What equipment at the Cabrio

Since we want to buy a new Saab convertible, I have a few questions about individual features, since we come new to the league of the Saab or the convertible drivers: Planned is a 1.8 Vector (since we need the vehicle rather for shorter distances and have the Volvo V70R to the lawn, and highly motorized front-wheelers do not lie down to me) Which sound system makes sense, since the acoustics in Cabrio is probably not comparable to a closed car? Do the returners make sense? W it is still indispensable, e.g. does it need a wind bulkhead?