Sorry, I do not read the whole thread.

Many parts of Inspira are shared with Lancer, even though different in part number.
Most of the parts, Proton simply mark up the price and end up much more expensive than Mitsubishi parts.

From what I know, the headlamp of Inspira are different than Lancer, hence the price different.

Price not same doesn't mean they are not the same.
For suspension parts, afaik only absorbers are made locally (also why it so affordable). Everything else is the same as Lancer, also much more expensive than Lancer (marked up price).

I'm not sure others but I'm not just consumers.

I'm operate a Insurance Claim Collision Repair workshop in Ipoh.
Sometimes I do purchase Lancer parts to be installed on Inspira for my customers (they are the same, except the packaging) at a lower price than Proton counterparts.

Review to some comparisons below

Lancer GT
Door Front LH 5700A557 RM2,671.50
Suspension Arm Front LH 4013A009 RM561.89

Inspira
Door Front LH 5700A557 RM2,138.60
Suspension Arm Front LH 4013A279 RM809.53

He might be right, coz my family operate a Proton Edar 4S in Ipoh.