You should not require a rear anti roll bar ,if you want the 1200 to handle neutrally ..If you require oversteer fit a rear anti roll bar .. the larger rear Bar the more oversteer

Rollcenter height dose effect Body roll ..the closer you get the roll centre height to the Cars centre of gravity the less the car body will roll over .. To change the front roll center height you use spacer blocks(mac pherson strut ) Between the steering arm and the strut leg
.. To change the rear roll centre with a solid rear axle it gets a bit harder as the roll centre is usally the center of the axle and Dosent change when you change to lower ride height on the rear unlike the front rollcenter which dose change with ride height ..So to change the rear height you require a watts link with a adjustable pivot point .. The pivot point height changes the Roll center height . it is best to use as softest spring rate as" Possible ", As this a allows the tires to follow the bumps and irregularities in the road a higher percentange of the time ..
Anti roll bars are usally THE last Tunning Aid adjustment you would use after you get your spring rates .Roll centres and alignment dialed in .
This informatiom relates to a acheiving maxium cornering power
..NOT ride comfort ..