I replaced the struts on my 89 244 with the bilsteins HD, I did not use any spacers and also did not use the bumpers at the top as recommended by bilstein. I did not change the mounts but wished I had in after thought. It is just a preventive type of maintenance for my peace of mind. For the amount you indicated I would indeed change them, after all you are going to use a stiffer type strut. As already said, If you are going to keep the car for any length of time it is worth it..I assume you are going for better handeling so changing them would make sense...Find you a good turbo swaybar for the front and rear and you will really notice the difference..