i dunno what u require, but , i do share my experience here....i am driving a civic eg 4 door..... 1st i installed full ultra racing bar except the front and rear ARB,hwl hi/lo adjustable (not too soft not too hard, 6k front 4k rear) i only feel car is solid then stock and yet still understeer if applied more torque during corner, next, changed to lsd gearbox, more grip on the floor, can apply more torque but still massive under steer when much more massive torque kick in when turbo spool... next, ultra racing rear 18mm ARB upgrade (oem 11mm), front not upgrade together, here come the interesting parts, FF car with more solid rear, going in round about around 90km/h and try to apply more torque, i turn the steering more like normal (cause normally always under steer) , miracle happen, i oversteer...
yes, seriously, oversteer, the tail is going out 1st, when i try to turn more in order counter the under steer that i normally got.......next day , mech finally got time for the front 27mm ARB installation, after install , it neutralize most the over steer, make it balance, but if u steer more some over steer noticeable, for higher speed, these bars tend to balanced the car between under and over steer....
for previous wira evo 4wd case (evo 4 engine, gearbox with evo 3 rear axle)
tein ha ultra hard absorber set up , 8.5k front and 6.5k rear , full ultra racing bar except front and rear ARB, handling somehow stable,but, when full boost accelerating at 30 degree corner and speed around 130km/h, scary massive understeer till i almost hit road divider(less then 0.5m distance), the understeer slide my car out wards even i try apply more steering angle, at these point, i understand what balance car weight distribution affect the handling , the under steer mainly caused by my 70% weight is in front and my total weight is heavier.....
so based on my experience, those over steer and under steer can be reduced or over come by correct weight distribution, suspension set up or adding UR bar like in my civic case(sorry bit off topic) .. however, in your case, if race spec or older generation AWD that the transmission are all mechanical type, example evo 3, my fren having full lock lsd on rear from RS version, it made the car sharp at high speed corner without experience scary understeer like in my case, some how still can over steer.....if modern AWD with electronics transmission control like the new subaru impreza .... somehow the system allowed the driver to tune the power transmit to all 4 wheels, example 60% rear 40 % front.....i do heard some mechanical lsd allow us to do that also, do correct me if wrong...
for RWD, sorry, never experience and get info of it, but i do heard with a set of good lsd that make RWD more traction on rear will made the car oversteer easily for example those drift car do this....
do correct me if i am wrong , i am still learning kid also..tq