Safari 4 is claimed as the world’s fastest web browser by Apple. Safari 4 brings a bunch of new features, including a flashy new Top Sites view, a completely redesigned Windows UI, and support for some impressive emerging Web standards. safari 4 beta got 100/100 on the Acid3 test. (Firefox 3.0.5 scores 71/100.) Safari 4 is designed for Mac OS X 10.5.6 and Snow Leopard (upcoming). Still many OSX86 user doesn’t upgraded to 10.5.6 yet. For the peoples who don’t have 10.5.6 and want to try the Safari 4 beta here we have a guide for how to installing Safari 4 beta on 10.5.5. You have to download 10.5.6 delta update in order to extract QuartzCore.framework from 10.5.6 .pkg.
This worked for me but if you want to give it a try do it at your own risk.
1) Change system version to 10.5.6 (by editing SystemVersion.plist in System/Library/CoreServices. Seting ProductUserVisibleVersion and ProductVersion to 10.5.6. allows you to install 10.5.6 updates including new security update without a real 10.5.6. and install Safari 4 beta)
2) Install Security update 2009-001 via Software update
3) Download 10.5.6 delta from Apple
4) Download Pacifist 2.5.2
5) Using Pacifist install and update QuartzCore.framework from 10.5.6 .pkg (navigate to QuartzCore.framework and press install. Upon request press replace files)
6) Install Safari 4.0 Beta Leo
7) Change system version back to 10.5.5
8) Repair disk permissions