I am running a 420LF motor in my rex and I am going to build another one. which motor do I get.
Iwant to have a bit more power but it's not for 3d.

430L 3550Kv

450TH 2950Kv

450F 3500Kv

??????????
All and any info appreciated

I've used a 420LF, and a 430L.......the 430L is SIGNIFICANTLY more powerful than the LF.

I just bought a 450TH, but haven't tried it yet.

I am not familiar with the 420LF, but the 430L is pretty kickin'! I took my Rex to the local heli field for the first time yesterday, and the nitro flyers were stunned at how much power I had in reserve. Anytime I punched full collective the Rex would climb like a rocket, and you could actually hear the rotor speed increase instead of bog down like many of them do, and I'm running a full 11 degrees on the top end. I am not flying 3D yet, but I'm fully satisfied that the 430L motor has all the power that will be needed when I reach that point!

I'm running the Astro 020 803T with a 13T pinion on my Rex. I have no bogging and have atleast comparable power to my Raptor 50. I expect the motor to last a very long time as most Astro motors do. The 430L is a bit more powerful and less expensive, but has quality issues. The end caps come off on some of the previous gen 430L, gold caps. The silver cap'd 430L supposedly has resolved that, but I still don't trust Align electronics.

The Medusa research motors are reported to be very good as well. The 28-032-3400 seems to be the most popular, and can also be run on 4S li-po's should you ever choose.