Yeah, easy.
Incar did one in 1997 with 4 12s, did 146dB if I remember correctly, which was bloody loud back then.
There were in a fibreglass box (around 4 cubic feet) firing up into a 15mm glass panel that acted as a port through the rear firewall and into the cabin. You have to do this or forget big bass, the boot is completely sealed from the cabin. A section of steel 800x150 was cut out and steel mesh welded back in for strength.
Alternatively 2 or 3 very good 10s can be fibreglassed in behind the front seats. Phil put 4 in an MR2 this way and a CRX is a lot bigger!
It's on their site
www.incaraudio.com.au AJ

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Owner of SPL King 2001, Hot4s Issue 81 Feature Honda Civic.
160.8dB from 2xMTX 1000Ds and 4xMTX T8000 15"s
Visit: INCAR Audiomotive [Edited 1 time by AJ on 07 October 2002 at 09:16]