yeah exactly as above, single turbo kicks in pretty soon and on low revs, unless other wise you have mannual set it up on hig revs which is offcourse very strange.
so simple trick ,
drive the car in 2nd gear and then slam on the accelerator
now if the car accelerates noramlly untill you hit the rev limmiter (e.g at 7000 rpm) and in between if you see a little jerk/missing and blue somke in back mirror, mean turbo is not kicking in. and take it to good mechanic.
other wise, you will see a clear difference in acceleration when turbo will kick in.
just putting in the stage 2 turbo right away will do no good to your engine and it will rather fry it.