yea, did this for helment clearance and for high weight removal. a real pain in the posteria
used an air chisle and die grinder with 4 1/2" cut off wheels and only punched two holes through the roof. (someone asked me if it was a hail dammage car) the whole project was done in about 4 hours and does remove quite a bit of weight. i used 6 aluminum straps to hold the stock sunroof in place, and filled the gap with clear silicone. works for me...
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Chuck Baader
SEDIV ITS #36
E30 BMW