Adding flaps and expecially flaperons to a Twin Star for the purpose of making slower approachs will only cause problems especially with the loss of an engine or in a single engine approach.

Many have increased the weight by using heavier engines than intended and modifing the nacelles for larger tanks and if this is the case the very best way to acheve a little more benign handling airplane is to reduce wing loading by increasing the wing span a few inchs or a bay.

John