I can say from first hand experience that their products are great. The quality is awesome and only general maintenance is required every now and then. I have the tein flex system and it is running strong with no problems. The EDFC unit is compatible with the tein flex and tein CS suspensions. If you looking for a hard race type setup then go with teh flex, but if you want to enjoy the road more without a super stiff suspension, go with teh CS.