System Upgrades

Hi All, Wasn't sure where to post this as I didn't see a section called system but here goes.

I am looking to improve my system. Components are listed below. What would you improve first (excluding SPDIF converter and speakers)

Linn LP12/Ittok/Benz micro Glider
Dennon cd transport-M2 HiFace-generic USB cable
Burson 160D DAC-Pre
Arargon 4004 MkII
Audio Research SP8 Pre

Thanks