Just seen this and wondered if anyone has tried it yet.
I don't know about this specific one but some of these theme packs will actually modify system files. (I think one even caused some problems for a lot of people a while back.. it may have been brico pack or one of those. I can't remember). Just make sure you make a system restore point before you use it.
Looks good, Haven't tried it though.
According to one user (bottom of the page) the previous version .5 was unstable.
I like that it backs up the system files its about to change, I still think it's worth making a system restore point first though.
If it doesn't require a restart maybe someone with power shadow running could try it for us