The following company is just coming out with a new catalogue. I hope it will be here shortly. You have to check your local emission bylaws. The TDI can be used with a catalytic converter. This means that there are no more Diesel smells and no more fuming.
Catalytic converters are however less effective in Diesels compared with gasoline engines.
The TDI is a fairly clean burning engine. It is becoming very popular in Europe. If any one of you has any ideas or resources, let me know and I will post them in the next letter. Eventually developments will be posted on a website.