Some questions about Millers Oils (NT, NT+, TRX)

[Turbo86]

I was wanting to order some transmission fluid this weekend and couldn't contact the guys at http://performanceracingoils.com so I was going to see if anyone on here could answer my questions.

On their website if you fill out their "which oil to use" form it says to use the TRX Semi-Synthetic 75W90 for manual transmissions.

Is it better to use their CRX LS 75W90 NT? http://performanceracingoils.com/crx-ls-75w90-nt/

And would it be even better to use the NT+?
http://performanceracingoils.com/mil...-crx-75w90-nt/

What is the difference between the NT and NT+? Is one of them more race-oriented than the other? Does one need to be changed more frequently than the other?

For reference I'm considering using it in my turbo 86, mostly street driven on the weekend (canyon runs and spirited driving).
Occasionally tracked (hpde few times a year, autocross more often)

[Turbo86]

If anybody is interested I got this response from Performance Racing Oils, so I'll be running the NT+:

The manual TL70 6 speed box requires an API: GL-4 SAE 75W-90.

So, yes you can use CRX 75w90 NT+ no problem; but if the vehicle is in warranty you probably shouldn't. If it is in warranty then we would recommend TRX SYNTH 75w90. The reason I mention the warrantee issue is that Auto manufacturers are very persnickety about their oil specs. Our CRX products have extra protection particles not called out in their specification. Even though the oil is better than what is specified, if the customer ever has a warranty issue with the trans, he might find himselfout of luck if they find out he was using the CRX products.