Hi,
If your site runs slow you need to be looking at things that have more impact on performance. These optimizations recommended by YSlow are like waxing your car to reduce wind resistance and make it go faster, maybe you can squeeze a tiny improvement out of a race car with this approach but it will not make enough difference that the driver will notice it.
It is a waste of time if you have other more important factors making your site slow such as cheap web hosting, deploying a debug build etc. If I had a dollar for every time people using cheap hosting like GoDaddy asked about improving their YSlow score I'd be a rich man.
This site is not slow and mojoPortal running in decent hosting is not slow.
see also this related thread.
Hope it helps,
Joe