1. Room treatments
~500€ for basstraps, 250€ for diffusers, 200€ for absorption.
2. Speakers
2600€ for B-stock pair of XTZ Divine 100.33. MSRP would have been 3560€.
1150€ for Arendal Subwoofer 1.5
3. Amplifier
220€ if I remember correctly for used 90's vintage Yamaha MX-50 power amplifier
4...