Finally i've upgraded my lovely Specialized Big Hit 2010 with better brakes (Avid Code), forks (Marzocchi RC3), rear derailleur (SRAM X7) and Truvativ Holzfeller crankset. Now my Big Hit meets all my requirements. Avid Code has a very good braking power. Marzocchi RC3 fork works very well for me despite it's a little bit heavy. SRAM X7 derailleur with a short cage is a perfect compromise between price and quality. Holzfeller cranks do their job, they don't creak, they are very hard and not too heavy.
Truvativ Holzfeller Crankset
Specialized P-disk wheelset
Avid Code Brakes with 203mm rotors
Azonic World Force 762mm handlebar
Intense DH FRO Lite 26x2,35 tyres
SBC chain guide
SRAM X.7 Rear Derailleur
SRAM X.Gen Trigger Shifter
Lizard Skins Logo Lock-On Bonus Pack - Peaty
KMC Chains Z82 8sp Half Silver
SRAM PG830 Cassette 8sp
Wellgo MG1 Magnesium Platform Sealed
Specialized Big Hit 2010 + Fox DHX 4.0
Marzocchi 888 RC3