They're very different cars. The closest thing to the 280TE in the US is the 300TD. The 300TE is of the newer body style and was offered in the US from 86-95. The 300TE became the E320 (no distinguishing identifier for coupe, sedan or wagon) in 94. There was a 300TD of the newer body style offered in the US in 87.

I don't imagine there's any great demand for 280TEs. It has its die hard fans but you're not going to get $4000 for one in anything less than an excellent car with full documentation.

Engine parts for a 81-up 280TE can be a bit of a problem because the M110 was not offered in the US beyond 1980. There might be unique sensors and such that you'll have to hunt for. Everything else should be easier to find because of the commonality with the same generation 300TD.

Sixto
95 S420
87 300SDL