Ok, I'm going to rant on this a bit. There was a famous American car company who, when looking at their costs, found that they had developed 6 different unique fasteners to hold the car seat down to the body across their line. Each one had development costs and manufacturing costs, and accomplished the same thing. It was determined that one of the fasteners was really over-engineered and could function for ALL applications and save the company a ton of money moving forward in:
1. Parts tooling costs
2. Parts manufacturing costs
3. Parts storage cost
4. Long-term parts supply costs
Now you could say each of those cars had more unique content, but it didn't actually do anything except drive costs up.
An f80 is a 3-series. It's always been a 3-series. It's a seriously beefed up 3-series.
For upfront and long-term reasons, I don't want 80% unique parts. That's ridiculous. 50% is an excellent blend indicating lots of new body panels, drivetrain parts, suspension, steering, and brakes. And of course interior bits.
However, we know that they are using unique parts when it counts most. This means that they STOPPED using unique parts where it didn't matter as much.
What does this mean for us?
More R&D and development dollars went into the vehicle's performance. Long term ownership will be less expensive for an M vehicle because some of the little stuff won't be 3x as expensive. And there's less opportunity for some uniquely developed part to be absolutely terrible because it's already been in use for 3 years.
As an owner of a ~13 year old, 127k mile e39 m5, let me tell you: It pisses me off when my front porkchop (read: lower fender liner in front of tire) is 2x the cost of a e39 540i because the e39 m5 used a unique part in that location. It's not a brake duct or anything performance related. It's a fender liner that has a thick rubber lip where it meets the body for God knows what reason - and it's 2x as much as a result.
In the e39 m5 crowd and many other older M crowds, it's a point of joy when you find a non-performance part that's shared across the line and therefore is a more reasonable cost
/Rant