I used the cheap ebay bags and regretted it. They would leak down in 3-4 days. Then one of them broke the lower plastic housing in half that supports the bag and the seller refused to honor the 2 year warranty saying they couldn't determine it was a manufacturers defect. The plastic literally snapped in half. Then I had to buy another one from another seller. That one had the lower mounting bushing made from too soft rubber and it squished out once I inflated the bag. My other car I bought the Arnotts, it will sit without dropping for weeks and haven't had any problems, plus they are easier to install as the lower aluminum housing is made to sit at the proper angle. Do it once, do it right, buy the Arnott's. Coilovers ruin the ride, I've driven a couple and they rode horrible.