ADS 10” subwoofer driver

I have 2 pairs (4 units) of ADS S10 10” subwoofer drivers. I cannot decide which type of enclosures should be used since the manual suggests both closed enclosure and infinite baffle types. But if I choose closed enclosure, only two of them can be used because of limited trunk space. While the IB allows to install all 4 units—under the rear parcel shelf of the ‘83 380SEL. So, regarding the manual attached, please advise me which way is better and should go for.

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