I also has a NT18T, the quality is very good. But you have to change the original shock into metal type shock.
It's very Cute and with speed. I love it! Same as my NB16. Both can running on street.
1) NT18T engine in made in JAPAN.
2)If you talking about speed. Then both NB16 and NT18T would not meet your requirement, as they can't compare to 1/10 or large scale GP car.
I buy 1/18 GP car is because I love mini size (just like mini size of RC heli), and with that size, they can have a Gas powered engine and with such high speed, it's really very attractive and satisfactry to me already...