350X has no limiter that I am aware of. Not sure about timing advance.
What I do know is that it is useless to "upgrade" your cdi from a factory 400EX CDI as they are completely done making power by 8000 rpm. Anything more than that is more wear and tear on your valve train.
If you raise the RPM limit on a 400EX you don't know when to shift in the first place.
99 416EX
12.5:1, XR400R cam, Ported, FMF Powerbomb header/White Bros. E-Series Slip-on, Hinson clutch, KN/open lid, 40mm FCR tuned for E85, KFX450R front shocks, Works Ultracross Rear.
08 KFX450R
Pro Circuit TI-4 Full system, KN intake, PC V, Hotcams Stg 2
10 Yamaha WR250R
Street legal dirt bike
99 Chevrolet Camaro Z28 M6
H/C/I/N2O All motor = 430rwhp/403rwtq 150shot = 591rwhp/649rwtq 11.4 @ 128 on regular street tires 26mpg
93 Eagle Talon TSI AWD 5spd
Evo3 16, 272 cams, Evo 8 Rods/Pistons, 560cc injectors, 2G MAF, DSMLink @ 17 PSI