Went through this last year or so. No real way to easily check it to be sure, as far as I know, without removing the cover and looking at the timing...
I recall the new assemblies being somewhat heavier compared to the original motor, regulator and bracket, but not overly so that I needed to readjust...
I would suspect an electrical issue before thinking the sender is bad. Clean up the connector to it, make sure you have no cracks in the wiring, and...
I disagree. If there is air in the line and you're struggling to shift when you first get in the car and turn it on ("cold"), shifting gets better by...