Likely not... as SU does not use PR as a factor. Though the fact your account does have that PR may indicate that your account does have some stumble power. If you have a huge network, lots of friends, a lot of profile reviews, you've done a lot of stumbles/reviews, etc, will be better factors in figuring out your SU power.
A PR3 will pass on link juice to all the pages that you have reviewed. You can try to post a blog post on your profile which feature some links to your blog or site. It helps.
Most, if not all, SU links are rel="nofollow" so there will not be much juice being passed. Also, as I said, googles ranking does not effect how SU functions, within SU.