Printed chassis for my line follower it can reach easily 1ms.
Required parts:
Arduino pro mini - 1 pice (non standard one from china with 8 analogs)
DC motors Pololu 1:100 HP - 2 pices
Dual H Bridge - TB6612FNG Dual Motor Driver Carrier
8 sensor line - POLOLU-960
And battery: Xpower XP01502ES 150mAh 7.4V
it gives very light line follower: 69.6g(with battery).

skmskm's 3D printer

No

Doesn't Matter

0.3

20%

speed 100mm/s, infill less is better(less weight).