You can get them here at Subsim or at...
http://forum.kickinbak.com/index.php
Mod and patch SH4 and you'll have a good time. If your looking for SH3 with better graphics, you're not gonna get it. Well, at least not yet...
BTW, welcome!
We bitch allot here, but we all love subs and will do anything to help each other out. That includes you too...