A Klein Quantum "purple haze" updatet with Carbon Weels, the Shimano 105 R7000 Groupset and many new lightweight parts.
Costs:
Second Hand Bike complete 700.- Euros
Second Hand Wheelset 250.- Euros
All new Parts 1500.- Euros
Minus sold parts:
Shimano Groupset -115.- Euros
Wheelset (Chris King) -650.- Euros
Total= 1685.- Euros
I'm not a pro mechanic so some things are not perfectly executed, but you get the idea.