Eight new seat gas spring shocks covering E30, E23, E24, and E28 seats — plus a custom tool for installation. The toughest part of this job is compressing the 400 N gas springs during install, as it takes much greater force than human hands can generate. We solved that by making a custom tool. The ends of the tool are 3D printed from PETG and have sleeve bearings. All eight shocks are 400 N and work perfectly for both the seat back and the seat base. They cross-reference to the following OE numbers: 52101965645 52101916601 52101965632 52101965646 Pricing (shipping included): Set of 8 springs + tool — $250 US/Canada, $260 international Eight springs only (no tool) — $160 US/Canada, $180 international Tool only — $80 + shipping ($12 Canada/USA, $25 Europe, $31 Australia, $34 worldwide) Email [email protected] for volume discounts when ordering 3+ sets of seat shocks.