the biggest thing to consider is how much / if possible retrofit is for these things so.
Unfortunately its not until youve had a mk5 you know whats a must have and whats not a problem!
Highline : possible but a PITA : for £50 was always a no brainer when ordering new , no a deal breaker but nice to have in a 2nd hand buy
MFSW : possible , but wheel + modules can make it expensive
Arm Rest : possible but PITA and expensive , can do without
DSG : lovely and improves resale
Bluetooth : easy to retro fit + cheap
Xenons : possible , but expensive if you do it fully 'legal' : I love them
Sunroof : no retrofit , can do without , but wish I had ordered one
Low spec would be a car without any of the extras added to the base ED30 spec (which has a few extras anyway)
Cars tend to fall into 3 categories , base spec no extras , few choice options where owner couldnt afford it all , or the full hit 'kitchen sink' cars