I purchased my springs direct from Prevost. They had two versions. There was the "regular strength" version, which is their current spring. If I remember right they were around $25 apiece. They also stock a heavy-duty version for converters like Country Coach, who hang chairs on the doors making them a lot heavier than original. These were around $40+.

The connection to the coach had changed a bit since my coach (92-93), which required I purchase a set of ball joints (wrong word, I'm sure), over which the strut ends snapped. About $3 per connector.

The good thing about Prevost is that they were in stock, and immediately available. The bad thing is that once I got the struts, being able to actually install back in some of the bays (like the water bay) was almost impossible without tearing everything out. Luckily my primary problem was with the front bay, which is completely accessible.

Note, you may also way to replace the door safety latches at the same time. Many of mine were bent/worn. They are about $7 per latch.

Ray