  Maximally Natural Supersymmetry, an unusual weak-scale supersymmetric
extension of the Standard Model based upon the inherently higher-dimensional
mechanism of Scherk-Schwarz supersymmetry breaking (SSSB), possesses remarkably
good fine tuning given present LHC limits. Here we construct a version with
precision $SU(2)_{\rm L} \times U(1)_{\rm Y} $ unification: $\sin^2
\theta_W(M_Z) \simeq 0.231$ is predicted to $\pm 2\%$ by unifying $SU(2)_{\rm
L} \times U(1)_{\rm Y} $ into a 5D $SU(3)_{\rm EW}$ theory at a Kaluza-Klein
scale of $1/R_5 \sim 4.4\,{\rm TeV}$, where SSSB is simultaneously realised.
Full unification with $SU(3)_{\rm C}$ is accommodated by extending the 5D
theory to a $N=4$ supersymmetric $SU(6)$ gauge theory on a 6D rectangular
orbifold at $1/R_6 \sim 40 \,{\rm TeV}$. TeV-scale states beyond the SM include
exotic charged fermions implied by $SU(3)_{\rm EW}$ with masses lighter than
$\sim 1.2\,{\rm TeV}$, and squarks in the mass range $1.4\,{\rm TeV} -
2.3\,{\rm TeV}$, providing distinct signatures and discovery opportunities for
LHC run II.
