Now sounds like a time for you to throw together a scrapyard special my friend. In the past, I ran a bodged box with a cavalier heater matrix, a mk1 fiesta matrix and two random fans which i believe were originally designed to go in a PC.. Got nice and toasty in there. It even masked the coldness coming from the gaps in my S3's body (before a mild resto) and because of the two fans being pretty quiet, it was quite a nice little unit with a fully variable speed. the fans could be adjusted anywhere between 4.3v (they stalled at 4.1) and 12v (rated maximum) - It wasn't the prettiest arrangement i've ever seen but fitted quite well with the rest of the S3's interior. It cost me like £9 to build, and at 12v moved like 150cfm of air which is enough