Considering rear swaybar-am I thinking correctly?

[R2D2]

Thought I might ask the remarkably helpful members of Yaris World to confirm (or not) my thoughts on the future purchase of a rear swaybar. I've done a good bit of reading here, including Loren's informative post regarding his UR 23 mm bar install.

As far as background I have an 09 Yaris 5dr LB with bone stock suspension. I still have the OEM rubber running max recommended pressure (44 psi). I'm a hypermiler so typically my driving would be considered "old lady-ish" by many. However, I do frequently roll hard through corners under slight throttle to preserve momentum and find myself "involuntarily" leaning into the turns. I also want to increase stability of the vehicle at highway speeds and in the wind. I otherwise do no aggressive driving or racing so from the reading I've done the 19mm bar from TRD or UR seem like the best "fit" for my needs. What do you guys think? Is the 19mm rear swaybar a realistic (and cost effective!) source of improvement considering my list of wants?

Also I should add I have the Toyota Platinum extended warranty-is the addition of a non TRD part going to cause headaches? I realize the bar us "minimally invasive" to the stock suspension, but you know how some dealerships can be!

Thanks in advance!

R2