in your position i would demand a base salary higher than current with the 6% on top. as said, they have headhunted you so make them pay for you.

money aside, because money is certainly not everything and job satisfaction is equally important imo, it sounds like it would be challenging for you, which would appeal to me. and you won't know if you don't try. if your current job is not all that challenging, then you can probably get back into it or something better if this one does not work out.