Hi,
I noticed that one of the rear springs on my 2005 Corsa(C) Sxi 1.2 was incomplete so I purchased a new pair from a local motor factors(Sutton Auto). I was hoping for K Flex ones as I'd previously fitted those to the front of the same car and remembered reading that they were OE fit to 1 in 4 cars.
Anyway the ones they had in stock were made by Green Line and boxed up as equivalent to the KYB RX6341(the part I'd hoped for).
I removed my old springs and fitted the new ones such that the smaller end coil on the new spring went to the top like the old(Original Vauxhall) ones were fitted. I then noticed that the bottom coil wasnt as tight round the cup as the old one. Partly because the bottom coil wasnt as complete as the original and partly beacuse the coil itself was about 1cm bigger(ID).
I've since ordered a K Flex KYB RX6341(it was only ?12 delivered off ebay)which is pictured below so I could see if there was a difference(I obviously cant measure the green line ones at the mo as they are on the car)
This is the K Flex RX6341 with internal top/bottom coil measurments;