I replaced the uppers in my W123 in about half hour a piece, without using a spring compressor. I believe the same should be possible with the uppers on a W126. The lowers are another story, and I would say about an hour a piece, half of that time is spent getting the old one out. I watched as my old ones were removed on the aforementioned W123, and no spring compressor was used in that instance either.
In short, do the uppers yourself.
"...rationality of thought imposes a limit on a person's concept of his relation to the cosmos." -Nash
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09 Jetta TDI