p90 optics (reciever change neeeded?)
 

can you put a p90 optics (standard on p90s) on a TR version, or are the top recievers different? I like the look of the FN one but i got the TR so i could use better optics, not sure if i made the right choice.

Better optics would be Bushnell Holosight however its fairly pricey. Fits on TR.

The upper receivers are entirely different, you'd need the RDS receiver. But trust me, any RDS you put on your TR will be a lot more effective than the standard P90 RDS.

unless you get the real steel optics to mount on to the RDS receiver...

That is true. Apparently they fit pretty effortlessly.

but cost an arm and a leg. i dont really understand how a 20mm reticle would be so effective.