The 4* 60 probably would shine with a .90. Mine is a 40 size and flys great with a 52 four stroke. An 11 X 5 prop gives it plenty of vertical, but not unlimited. The Tiger 2 is also a 40 size plane, and a 52 size four stroke or a 46 2 stroke will pull it around quite well.

The differences between the Tiger and the 4*? The primary difference is in the wing. The Tiger's wing is thinner (and a different airfoil), and this can make all the difference in the world when it comes to wind penetration. Aside from that the Tiger and 4* 40 are pretty similar in size and general planform. The tail surfaces are different in appearence, but similar in size and relation to the rest of the plane.

Good luck with your choice.
Dennis-