The newer generation turbines (Jetcat P120 - BTW, I own one, ask Spiderjets, he sold it to me- the Simjet 2300, 3000, TJT 3000, AJ JG100 Eagle, etc, etc.) have twelve vaporiser sticks in the combustion chamber, as opposed to six in their older less powered brothers.That's what makes them more powerful. Also, they feature different compressors, diffusers and shafts/shaft tunnels as well as more sofisticated exhaust cones. Not a lot has been invested in the rear parts except in the case of TJT/AJ where the turbine wheel has been completely re-designed.

BRG,
Chris