I have a new box of TRW brake pads here and took a look at them, they look different to yours for the front slightly, mine is a 94 Turbo onward model. Being a 91 yours should have the smaller brakes. DB308 according to Bendix are for non-turbo MR2's up to 1994, so not sure what brakes you have fitted as looking at the image on the Bendix website they don't look like yours either! Maybe post a pic of your caliper? Also i'm not sure if Bendix HD's will hold up on a track day......