(Note: i haven't read on to the following posts since this one.)

I think Kris should NOT feel guilty at all. sure, maybe he can think about and decide he really wants to switch.
BUT, my guess would be that the reality is that one can make a much better living as a car mechanic than as a bike mechanic - this is a "problem" of our soceity and the car-centric culture, but it is not Kris' doing. People are going to drive and pollute and whatnot regardless of whether Kris earns his living by repairing cars (and yes, i know that if ALL mechanics revolted then it would not be so, but we all know that is not going to happen)
As long as Kris feels comfortable doing his job then so be it.
and Bekologist, i would agreed with many of your points in the thread, but i don't see it quite right to dictate that someone should feel guilty for his profession (unless it has to do with dishonesty or illegal activities or such)

as an aside: 2 years ago as i was looking for a new job as my old one was just not so exciting, i found a REALLY interesting opportunity - a well-paid position for a successfull company putting a lot of money into research in an area i found technically VERY interesting... but it was an auto company (BMW). at first i thought there was no way i could work for an auto company. then i thought about it a few days and decided that i should apply --- there wasn't anythign "evil" that i would have been doing at the job and if i didn't do it someone else would and maybe i could some how do something positive. (in the end it didn't matter as i applied and it went nowhere). in private sphere i have since met 3 people working for BMW (HQ is located in Munich) who are car-free - it's a job and in their private lives they prefer to ride bikes and the train.