Except for testing most this advice is awful. jQuery is 31KB not 86KB. CSS3 is or has plans to be hardware accelerated on all major platforms.
Also what exactly is your claim on how size is greatly affecting performance? That Android takes a long time to deflate a large zipped javascript file or that it takes a long time to parse a large javascript file or the large javascript libraries are ineffecient? Do you have any evidence on these things?
jQuery 1.6.2 is 94KB minified. Gzip compression is not applicable here because the code being executed is not 31KB, that's just the download size.
The amount of JS that has to be interpreted by the browser does noticeably affect performance. At least in my experience testing and building webapps for mobile phones, over 100KB of JS and many devices start to manifest performance issues. I find it interesting so many people here question JS size affecting performance, when this has been the main focus and selling point of browser development for the last year.
CSS3 animations and gradients are not really feasable for anything but the iPhone at this point. On HTC devices running Android 2.3, just adding a CSS3 gradient to each item in a list slows my scrolling speed significantly and introduces stutters in the scroll, versus using a PNG of the same gradient I'm using CSS for. This is just one example of many, but CSS3 support is very shoddy on devices outside of the latest iPhones.
Also what exactly is your claim on how size is greatly affecting performance? That Android takes a long time to deflate a large zipped javascript file or that it takes a long time to parse a large javascript file or the large javascript libraries are ineffecient? Do you have any evidence on these things?