After months of "thining about it", I finally went ahead with getting a modchip. Got my PS2 back last night with a Messiah 2 fitted and finally got to try out my NTSC imports. So far so good. It works a treat
I have only tried it with PS2 pressed dvds, PS2 originals and PSX backups. Don't have any PS2 backups but I'm feeling pretty confident about them working fine.
BTW, thanx to Bighap and BG for your helpful advice along the way, Much appreciated.