well i fly mostly 50s n 60s too but i like the smallness of these too as youcan fly these in your garden without the neighbors getting worried of it crashing into there home ect. funny though as their engine is still perhaps a bit noiseyer then say a raptor 60 . the engines can be a bit tempermentle sometimes too.. use a good fuel with aprox 15 persent nitro and use a filter on the fuel and it should be fine. i run mine on 20 percent and its fine i think but if you do get more nitro then put in another copper O'ring to lower the compresion a tad...
btw you can get loads of spares on german ebay for these and also i see you can get scale fuselages .i might get one one day