OK, back to basics.
Ollie, I can't exactly work out what specific area of the handling which is of concern to you? You mention the need for "stiffening", and "lowering" - yet your only concern, from your post, would seem to be body roll on turn in! What about "mid-corner" poise - is that OK? From your "hunkering down", I would actually deduce that it is OK.
The way I read it, if it is only the roll on initial turn in, then uprated anti roll bars would be the most appropriate remedy. This would not affect the comfort, nor the "speed-bump to front splitter interface", which stiffer and/or lower springs would. You are rightly cautious about lowering - as this can upset the geometry/wheel alignment. It shouldn't be too much of an issue on the front, as it has the McPherson struts, which are reasonably tollerant of lowering. However, the rear has fully independent multi-link suspension, and that type of arrangement does not like being lowered, as it will bu&&er up the geometry.
Give us more detail to your concerns.