My digital setup , still not satisfied ?

Hello
I have the below system and thinking to change the digital player

The car: Seat Leon HB
Amp 2 X Audison Thessis Quattro ; total 8 channels to run 4 way active system
Drivers: Thessis Orchestra 3 way Active
Subw: Pioneer 12" Slim ( inside spare tire ) sealed conditon
DSP: Audison Bitone.1
SFC unit for sample frequency converter dowmsample to 24/48Khz if anything bigger is sent
Transport: Pioneer 9310bt ( custom built VW unit ) ( DVD, NAV, Bluetooth, USB, AUX, Iphone Cable to connect my iphone4S , running 1 X RCA to DSP
Digital Player: WD live ( hidden , remote control receiving point extended ) 1st Gen ( Playing flac files) running 1 X optical to DSP and composite video out to Transport unit to see the file name.

All my system is working ;
My problem is the slow and sucking WD live when connecting the 500 GB HDD,which has 300 GB of FLAC files.
WD often stuck and has to be restarted ( you have to restart the car for this )
It also takes alot of time when you try to find a track.

I was concidering Logitech squeezebox touch to add with NAS system ,( although the unit is being discontinued , was after sound quality )
I have the question what do I need to run it in car ?

SBT + HDD with NAS system + small wireless 4 port Router
Connect SBT to HDD with LAN cable ?
How to connect the rest as dont want to connect the HDD to SBT through USB only.
Do I need to connect to internet all the time ?
CAn I distribute iphone shared connection so that SBT can reach to internet for internet radio ? and otjers ?

Thanks

Thanks alot for the update.

The reason of FLAC is to run Digital signal from media player to my DSP which doesnt DAC but sends out to AMPs which DAC before sending out the signal to speakers.
There is no RCA connection between my DSP and AMPS , all connections are done with LAN cables so everything can be Digital till the end if it starts digitaly .

If we skip this indexing issue, is there any player that will work without any trouble ,
- see the file names when seaching files in bigger fonts ?
- dont stuck when starting 100 MB audio file.
- able to search another file when one isbeing played ?

Am I requesting alot ??

I am considering a simple computer at the trunk to make things faster if SBT is not the solution as it will cost lower nowadays.

regards