Turboale, It's hard for me to say if the new sway bars would affect handling more than bilstine shocks/struts. I don't know if volvo puts a more agressive valving shock/strut package on their "R" cars like my 855. All I can tell you is if you have stock sway bars on your car whether it be a T-5,R or whatever you will benefit from installing the IPD sway bars. I still have the stock struts/shocks on mine, but I am also sure that new bilstines would be an even more of an improvement if they were put on. How much I don't know but I'm sure it would be noticeable. I did put bilstines on my 91 Z28 camaro a few years ago and compared to the stock ac/delcos that were on there it was like night and day. I have close to a hundred thousand miles on them, yes a hundred thousand miles and they are still rock hard. Feels like they are still new. By far the best strut/shock avialible in my opinion. But they did raise the car slightly and it took some time to get use to the new look, but eventually some eibach springs took care of that. As far as the spining inside wheel I don't know if sway bars or struts would help that. I still have it if I'm not smooth on the power application in the turns. Alot of that has to do with weight shifting and wether it's biased to the front or the rear. when I'm really hustling through the turns I've been known to modulate the gas pedal, but applie the brakes slighty with my left foot to shift the weight to the front tires to keep more traction there. It's a driving technique and takes some practice to keep from spinning out, but once masterd you'll have people wondering how your pulling away from them in the turn with your brake lights on. Hope this helps with your decision. Sorry it's so long too. post back if you feel the need.
MIKE