I have just finished fitting a light upgrade to my Roadster which also uses 7" round lamps. Being a Jap import it came with pitiful sealed beam units which probably didn't bother the previous owner living in London but which were scary on the way home to Devon.
I have fitted a pair of Raybrig clear lens units after seeing good reviews on the MX5OC forum. They take an H4 bulb and drop in in place of the sealed beams. They should fit a 924/944 also, although as you can see in one of the pics the 944 light has 4 tabs attached to it whereas the Mazda has a traditional retainer ring to hold a bare unit in the frame. If something could be fabricated (quite easy I imagine, probably by attaching the 944 style tabs to a ring from another car) to hold them in then they would be a good upgrade to the 944 also, even for those with Ice Shark kits and up to 135w bulbs according to the packaging.
edited for comedy typo
I have fitted a pair of Raybrig clear lens units after seeing good reviews on the MX5OC forum. They take an H4 bulb and drop in in place of the sealed beams. They should fit a 924/944 also, although as you can see in one of the pics the 944 light has 4 tabs attached to it whereas the Mazda has a traditional retainer ring to hold a bare unit in the frame. If something could be fabricated (quite easy I imagine, probably by attaching the 944 style tabs to a ring from another car) to hold them in then they would be a good upgrade to the 944 also, even for those with Ice Shark kits and up to 135w bulbs according to the packaging.
edited for comedy typo