My experience with pulling the fuse on a Boxster is that with top down and at low load and/or low engine speed difference is negligible.Does the Boxster benefit less from disconnecting? I am just thinking that with the top down it does not play as large a role?
With top down and hammering it difference is much more pronounced.
With top up the difference is very pronounced, and I would actually say that the car with fuse pulled has to little exhaust noise with top up.
Luckily i rarely drive it with top up.