Saracens square off with Clermont at Twickenham on Saturday and two years ago the French outfit made light work of them with a 22-3 victory.
However, Kayser believes that this time around his side will face a tougher task due to the attacking prowess of Lion Mako and his brother Billy.
"There are a few key changes in their side since our last meeting; the influence of the Vunipola brothers is huge," said 29-year-old hooker.
"They still have the same style of rugby, they are very clinical, very well-organised, their strategies are well in place.
"And it's probably the most physical rugby there is to play, in terms of intensity and the number of phases that they are willing to go through to put the defence under pressure.
"So I think that's where they are really, they've got threats everywhere, either forwards or backs, I just think they are more of a complete side than two years ago."