Underpowered!!?? you should do a little more reaserch before posting comments like that i have a 1985 230TE and that thing will out perform any 300D,TD or CD that i have driven, and that is with the A/C on!
i work at a mercedes shop here in san diego so believe me i have driven many diesels. have you owned or driven a 230TE?

get the 230TE and keep it original. thaose cars are quite rare in the US, it has the same basic engine as the 190E 2.3 but with a larger displacement. i so far have been able to get every part i have needed, a few had to come from germany, but took a few days. do you have any pictures of the 230 you are concidering?