alexus
by right, anti-roll bar should help.but i see no point with the current antiroll bar in market can do that job at all.no offense, my opinion.

i've install UR antiroll and front strut bar..for me..i can feel the improvement  i think much better if change rear stock spring also..just my opinion

alexus@
if you want to reduce the bodyroll, best way will be changing to slightly stiffer suspension setup and wider tyre(saga blm stock tyre sux).
all round anti roll bar is just an add on which help if you always use the weak 1.3 saga for touge 
bear in mind, with front strut bar installed, you will lose the privilege of doing alignment on any single side. you have to get both done.

SiuYi@
your fc was good! i tested around 0.20/km on ron95. auto. 80% city driving. the other 20% was 140km/h at mmr2.
btw, friend's saga is almost become 1.6cc already. power more linear and smooth. suprisingly quieter compare to before the conversion done.
does not require heavy foot to push. but happy revving when going uphill.
change gear(stock auto, need cog change for a suitable ratio) at 6.8k rpm. will send to puspakom once the happy revving problem solve.

erm kinda, can say more effective or proper solution, if handling and stability is important for you.

alexus
IMO, lowered sport springs, with r15 aloi rims, with proper front strut bars definitely will give merits for handlings. but bear in mind, we are not talking about track race or drift race.