Not a purist. Those aesthetic choices are subjectively bad.
The steering wheel is a large part of what that car is about, and it is not an upgrade unless it is the later factory Td5 type, and even then, anachronistic, and arguably a step down for size reasons. The old wheels are legit and big for a reason. Diamond plate ANYWHERE that isn't the front wing tops (for step) is not an upgrade. It usually alludes to hiding rust.
Why would any of those things be "necessary"?
You're aware the 90 and 110 have had turbo diesel options since 1986? Power unlike the above aesthetic choices, is a perfectly suitable reason for an upgrade. The cummins 4 cyl is fine.