As I have mentioned, you have to learn to do a slight lift to get a smooth shift, especially in S5/6. Just keeping your foot on the floor will give a very abrupt shift. And if you can beat the car in S5/6, something is wrong with the system.
As fro fluid, are you talking about the tranny fluid or the actual SMG hydraulic fluid? The SMG hydraulic system should have the factory hydraulic fluid, IMO.
I no longer use RedLine fluids in any of my cars. I use BMW LTF2 fluid in my trannies. But Royal Purple or Mobil 1 are also good choices.
'95 Alpine M3 LTW
'00 Dakar M Roadster
'02 Topaz M3
Red/White SRF #4 (Chassis 561)