i flew a 120sr on my dx8 this week and i honestly wouldnt upgrade anything, would just be waste of money.
use it to get all hover oreintations 100% then get something else.
flying in the driveway i never notice a toilet bowl effect and with a slight breese going so slight i was full cyclic to just maintain a hover. i then whipped out the mcpx and the guy was amazed he didnt fly either and the 120sr was his
120sr is perfectly good as stock bird it is what is is and no amount of mods will change that, its just a big msr