Both methods are safe if the correct spacer is chosen and fitted correctly.
Which is safest is debateable.
IMHO the hubcentric type where do do not have to swop out the studs is the favourite, granted a few pound more expensive, however much easier to fit and remove when required.
These are what I run on my track 650bhp Zed Roadster.
Eibach is the market leader and if you want the perfect stance then 20/20 or 20/25 is the way to go.
In stock and good to go same/next day
Drop me a pm if I can help you further.
viewtopic.php?f=157&t=42415
Alex