stephen newberg:
There will be other opinions, but in general, there is not a lot of HP gain to be had from altering the exaust system, SHO Shop version or otherwise. Most people seem to agree that the main advantage is in improved sound, if that is what you are after.
I believe the SHO Shop does the pinned cam fix, which tends to be rather expensive compared to welding. You might want to contact Kirk, one of the board moderators (I think his handle is 'shodown' or something similar). He is our expert on cam welding on site.
As per the suspension, I do not think the SHO Shop offers the most useful suspension mod any more, which is a Front Strut Tower Brace, but I think you can get one from MidWest SHO still.
pax, smn