I would shift around 6.5K on your car... look at your boost curve falling on its face after that ... your loosing 3psi in that 500 rpms afterwards. Your just blowing hot air and hurting your IAT because your heating the shit out of them. The next gear is automatically much hotter then where your IAT increased 10F inspite of the meth ... imagine what it would be without it???
I dont know what your boost set point is but it would be nice to see that also. Your ignition advance looks good in terms of that its getting advanced throughout the gear, but you could do better with higher meth and higher octane rating in your gas.