With the band pass box, you will have to make choices (box volume, number of ports, port orientation and total port area) to determine the enhanced frequency. With the sealed box you will have to determine optimum volume for your speaker(s) of choice. All of these choices can be determined from the information that comes with your speakers.

Sound quite simple but calculating a box is pretty complicated. But car-hifi stores usually have some prebuilt boxes - band-pass and sealed ones - at low costs. Even if such prebuilt boxes are not calculated for your special speaker-chassis you'll get a good compromise between afford and quality.

TeeMcBee
Got my Mk2! # 080000143