Try and return the engine to Thunder Tiger first to see if they will repair it for free as it should still be under warranty or damn close to it. They are very good when it comes to resolving these types of issues in the cutomer's favor.

If you have no success with getting TT to repair the engine then there are other choices for your Raptor 60. I fly an OS 61SX-H WC in my R60 - plenty of power for 3D or the OS 70SZ-H should have even more. YS 61 or 80 will work nicely but I think you'll need to change fans.

BTW - A Tower 75 will not work in this application as we are talking Helis engines - not fixed wing engines.