That's another matter. How much keeping affects one's batting. I would like to closely examine those matches where Sangakkara kept. Will respond back.Even though Sangers only averaged mid thirties with the bat when keeping cf. Healy's high 20s? Anyway, Sangakkara is not the worst example of this - he at least kept and kept pretty well in many tests.
Healy vs Prior/Akmal: easily Healy.
Healy vs Gilchrist: easily Gilchrist
Healy vs Flower: easily Flower
Healy vs Boucher: not sure
Healy vs Sangakkara: Sanga but I will have to check the above.