Similarity degree of Fourier algebras

We show that for a locally compact group $G$, amongst a class which contains amenable and small invariant neighbourhood groups, that its Fourier algebra $A(G)$ satisfies a completely bounded version Pisiers similarity property with similarity degree at most $2$. Specifically, any completely bounded homomorphism $pi: A(G)to B(H)$ admits an invertible $S$ in $B(H)$ for which $|S||S^{-1}|leq ||pi||_{cb}^2$ and $S^{-1}pi(cdot)S$ extends to a $*$-representation of the $C^*$-algebra $C_0(G)$. This significantly improves some results due to Brannan and Samei (J. Funct. Anal. 259, 2010) and Brannan, Daws and Samei (M{u}nster J. Math 6, 2013). We also note that $A(G)$ has completely bounded similarity degree $1$ if and only if it is completely isomorphic to an operator algebra if and only if $G$ is finite.