I have raced SuperGT cars in several championships. The Loctite is a very good car but the NSX Takata Dome '03 (not the premium '06 model) is fractionally better. I won the race at Tokyo with a Takata at 607PP and my qual time was 1'31.5 (free run, no slipstream).
In the championship the Takata '03 had 607PP, the GTR 613PP, the Lexus 615PP, and all the other cars 618PP. The Takata was still the best car. If you use the Takata at 600PP and all the other uses the same PP, you will have a hugh unfair advantage. Same goes for the Loctite, but it just a tad slower than the Takata.
If you will use only 600PP for all cars, I would recommend you actually ban all standard NSXes. Then pick any premium GT-R. It's the best of the rest.
Btw, Tokyo is a bad general tuning track. Given its high speed corners, I fast set-up has a lot of oversteer built in. My Tokyo set-ups always ended up very unique, and the car was almost undrivable at other tracks with the Tokyo set-up.