There are two different version here in the USA. PJ Grady sells a door lift piston (strut) that is identical to the OEM strut. The piston is set to pressure to coincide with the torsion bar. I purchased a set of lift pistons from DeLorean One in California. The pistons are slightly overfilled with pressure to give it a little extra kick. However one caveat...do not let the doors "fly open" as the force can rip the mounting stud off of the door opening Best Wishes, Michael