the understeer problem with rx8 and rx7, is caused by the driver
for most of the part. for expample, in akina, in those consecutive
corners, ppl tend to turn the steering wheel lock to lock, that my
friends, will induce big under when you into the 2nd corner and so
on. Try use the MMT driving technique, even in tight corner, try
not to turn lock to lock, instead always counter steer in a
microway.
Also there is another technique, that is when you about start to
turn, shift down and then shift up right the way (r34, r32 is a
must), you steer angle will be increase to the direction of your
turn. for example, akina hard right, you 're doing 165-170, do a
out-in out, after you brake at out, maintain in top gear, release
gas and turn and use the shift down/up (all in one motion), at
apex, down shift and step on gas at the same, exit and upshift if
you dont kiss the wall. try that, you'll see some significant
shaving in time. 
