27.5 wt is awfully light shock oil, what piston are you using with that? If you are using the orange or blue ones, you are going way too light with your damping. You can try the black pistons. See what pistons the other guys are using.
But if you are using the orange or blue pistons, I'd stick with that for the rear shocks and go with red pistons for the front, and just go with heavier shock oil. Try going 30 wt front and see if that helps with the same 27.5 wt in the rear. If it does, but not enough, then try 32.5 or 35 front, and change out your rear oil to 30 wt.
Also, make sure your ride height is arms level front and bones level rear. If your ride height is too high, that can cause bouncing too and is a fundamental problem in most poorly setup buggies. Too low of ride height can cause chassis slapping and bouncing too.
Make sure you are running 0 toe up front, or even just a small amount of toe in, that will make your buggy so much easier to control. Make sure your camber isn't too excessive either, keep it between -1 and -2 deg front and rear. Too much rear camber and it will make your buggy seem real loose in the straights.
I hope I have helped
High Desert Raceplace, Grand Jct CO, Sanwa Exzes Plus Stick Radio, Spektrum,Thunderpower 230g, Modified Tri-Nut Novak GTB2, Ballistic 4.5t 550, 5.83lb SCTE Ten, Novak Sentry Brushless Dyno, Crossweight Setup Station, Junsi 20A power supply Icharger 20A Charger,TP610C, 22B, Novak Edge, Novak 13.5, SC10, Havoc Pro SC XDrive, Ballistic 17.5 Matthew Joseph Cordova