91TS ignition module interchange ...

Does anyone know what years/models cars/engines have ignition modules/coil packs that will interchange with my 1991 98TS 3800 engine. Are some models better than others, or are they all similar? Mine is not a supercharged engine. Although I can return the part to the wrecker, and trying to find a clean looking part, is there a quick and easy way to test one of these units so I don't have to go back again for another. This wrecker is fairly big, so there's an abundance of 3800 engines in all years up to the mid-90's, and even a few supercharged Buick Ultras and and the odd Olds 98TS's now and again. Any help would be appreciated. Thanks.