Have V4 US Model, looking for non-swap mod

[Spicules]

I have what Im pretty sure is a V4 US PS2. Looking at all the information from various sites, the messiah seems to be the way to go, and since they're selling the messiah that is compatible with the V4 on Hong-Kong Toys for $70, it seems the cheapest way to go.

My question is, is there any type of disadvantage or special instrucitons to use this chip on the US model?

Also, what is the deal with the messiah clips? From what I understand they just make the installation easier. When I go to the site for them, there is no price listed, nor real explanation, and they never contacted me back. Anyone dealt with them?

Thanks