$300 a tire can pretty much buy you any worthwhile street tire out there, so now we're talking. I see you have 18x9 Drifts, which isn't a bad wheel but it is too narrow. Ideally you have a 10", but the ever popular (but heavy) 9.5" GT500 wheel works very well. Can you pick up a set of those in favor of the Drifts? Just as a side note, I am trying to trade my 18x9.5 GT500's for 18x9 Drifts for street duty, just sayin. Lol
Are you going to be doing just autocross, or track days as well? If just autoX, can't really look anywhere else than the Rival S or RE71r. But if you're going to mix track days in there, it's going to get expensive trying to keep the BFG or Bridgestone under the car because of how quickly they wear. It'll be some damn fast laps though. The Star Spec, RE11, AD08r, and RS3-V2 all would be better dual purpose options in my opinion because of tire life. The 265/35/18 and 265/40/18 AD08r spec out to be larger than every 275 tire I listed above in width, so don't be afraid of having it say 265 on the sidewall, it's not one. I think those will be my next track tire aside from the slicks. Only bummer with them is that they are a 140 or 180 TW, so could get you into trouble for autocross classing if you get that into it.
The NT01 is a great bargain tire, but I have no idea what that does to you for autocross because it is a 100 TW.