User blog comment:Mr. Mysterious Spyman/(Repost) Multiplayer Cars List (T&T)/@comment-30294077-20171105200450/@comment-27736210-20171106002020

Find the MAX + PRO top speed without the Tuning Kit.

Find the MAX nitro. Subtract the default nitro from this. Multiply the result by 0.1. Add this to the default nitro. (this is the nitro + Tuning Kit).

Add this to the MAX + PRO top speed.

That is the speed of 0400 5050.