I've got a 1984 300 SD. Smokes a lot on start up and a little going down the road, and hard to start in cold weather. I've tried several of the diesel injector cleaner additives with no avail. Unless someone has another suggestion, I'm thinking that I will replace the injectors. Any ideas?

If I do replace the injectors, I am tempted to purchase the reman. Bosch injectors from one of the internet sites. Can anyone share their experiences with reman. injectors?

Final question. If I do replace the injectors, are there any seals, gaskets, etc...other than the heat sheilds at the tip...involved (I don't have any manual that covers the replacement of the injectors and I'd hate to take out an injector and find that I needed a seal that I didn't have.)