Danny, the original leather seat had very good comfort in it, but on the track, I also found myself sliding quite uncontrollably, I felt like the seat is too big for someone in like me... (5-7, 150lbs). I went to the bucket seat mode, (recaro Spg) what I found out was very surprising, without the 4 and 5 pt. harness, I found myself's butt sliding towards the front, and (underneath the seat belt) after couple turns!! My problem, I found later, was that I didn't bolt the seat belt throught the harness holes and seems like that's the only way to get it safe for street and track use.
To get back to you before you purchase the racing seat and harness, getting a reclinable bucket would be a good start if you don't mind the little weight penalty (vs getting the full bucket).
People also have good results with CG locks, and knee protection.
I remembered before I had my recaro, and without CG locks, I had the following procedures.
1. Grab the steering wheel real hard get ready to duck when braking....
2. once you turn the wheel, you must lean your knee (and nsx's tunnel/console) is very good for you to rest there to get the upper body control. (Not realizing that until I drove my friend's STi on the track, OMG, I don't know how to drive with that light steering wheel and my body leaning towards my buddy.....
)