Get a factory rebuild!
I have been down this road before.
The dealer priced a factory rebuilt one at $1200. In retrospect, I should have jumped on it.
You're right in that it's a straight forward job to put in, but I was in there 4 or 5 times with bad used ones or improperly set ones over the period of a few years. That gets tedious.
Search my prior posts on this one.
'84 190E 2.3
'83 Porsche 944 (track car)
'84 Porsche 944 (parts car)
85.5 Porsche 944 (sled)