i hope to be in the market for a 4x4 saff in the next few weeks

my intension is as a daily drive, its took me years to convince the mrs and her only pre requisite(sp???) is that it is a daily drive and we sell our v6 mondeo as she refuses to spend that much and sit it in the garage

how reliable are they everyday in say stg1 tune?, whats economy like?
only do around 800 miles a year anyway so it wont take to much grief

is the msd closed loop system worth considering on this level of tune?? or is that better left for greens and above??/

all opinions appreciated

cheers