I had several cars in the 80's using H4 conversion housings (Scirocco, Mustang, & Corolla GT-S). I went with Hella E-code housings each time and was not disappointed. They are still made too and a bargain. OP, before you make the jump to HID's, try a quality H4 60W/55W halogen bulb set. The combination of better bulb, lens, & reflector is terrific.you will have to convert your 'sealed' headlight beam to the H4 housing.
you could buy the housing at your local auto parts store or ebay.
and as stated above, purchase an HID kit as well.