To each his own. Obviously not everyone is a DIYer. If you didn't enjoy the chase you're probably not cut out for it. I just paid $84 for an O2 and it will go in in about 20 minutes. When I guess wrong and put in a part that doesn't fix the problem I chalk it up to preventive maintenance. But agreed -it really doesn't make sense to do it both ways - invest your time, abort, and then spend the $300. I personally question whether it makes economic sense to own these cars (e.g. a 94 MB) if you go the $300 route. But again to each his own.