What's a good (easy) way of replacing the trunk lifts on 140-160s? Once the trunk is up they are extended and seem to take a lot of force to compress them so they unhook from the body side, and these are worn out as they don't support the trunk well. I don't want to brutalize the old thing if I can help it. I know, it should be easy...

Dave's method works, but you don't need the tool or an assistant.
Get some good wire and a pair of nippers. Close the lid on yourself and when the struts are compressed as much as you can ( maybe you'll want a flashlight too) wrap the wire around both ends a couple of times, cut to length so you can twist the ends and take up any slack.
When you open the lid, the wire holds the strut compressed and it will come out. You may have to tap one end off, but there will be room.
Compress the new struts in a vise. I used a woodworking cabinet clamp. Wire the compressed strut, and make sure you leave the part of the end of the strut where it will press the body or hinge free of the wire, or you'll be pulling hard to get that bit out.
Again, you put the compressed strut in place, close the lid so you can line up the points of contact, and cut the wire to let the strut expand into the load.
If you didn't keep the wire out of the mount, try to pull it through.
Think I learned this somewhere on the board.

The tool to remove the trunk struts looks like a flat bar with the ends turn 90 degrees, split to fit the flats at each end. One person climbs in the trunk and an assistant closes the trunk lid enough to slip the tool onto the old strut--when it's in place the assistant opens the trunk and the strut stays with the tool. The worn strut can then be removed from the tool.
You'll have to compress the new strut by hand or in a vice - enough to install the tool onto it and then reverse the process in the trunk. The struts can be tied with mechanics wire but the little bits left after snipping the wire will remain trapped. -- Dave

Thanks guys! Good to know it wasn't just me then, not able to easily figure this out... Quite a production!