For ultimate auto-x the Ra-1 and NT-01 are great, but really meant more for road course and as such take time to get up to temp. Kumho and Hosier make auto-x specific compaunds that heat up extremely fast but do not last very long.

That said, I love the Nt-01 and feel it has a slight edge over the RA-1 especially if you intend to run them full tread. Both are made by toyo, but the RA-1 is an older design. RA-1 is a great tire and if you can get it for far less, that would make up my mind.

Those prices above are extremely good. The RA-1 really should be shaved to at least 6/32 if not 4. At full tread, they can chunk a bit.