From my experience with 2x MSC cars - RS200 and 6R4 - I would say no to your "are they faster?".
I haven't run either of these cars against a C4, but I've got loads of other SCX cars and on my predominately Scalextric Sport rally track, which is mainly R1 and R2 with the longest straight only 2mtrs, the MSC cars are among the slowest because they are very hard to keep in the slot.
The detail on the cars is brilliant, but I'm unlikely to buy any more, and if I'd have paid the normal asking price for them I'd have been very disappointed. Detail is all very well, but handling is of greater importance to me.
In fact, I'm having problems with the rear axle on the 6R4. I can't get the crown to grip the axle. The grub screw has been tightened that many times the the allen key now spins in the screw and the crown is still loose . I'll have to get a better crown.
Not impressive for a £50+ car.
The belt driven 4wd was never the brightest of ideas, either. For the band to be tight enough to actually drive the front wheels of my MSC cars when they are under load, the front axle is pulled out of line.
To sum my feelings up.......... Buyer beware!
Just my 2p.
I haven't run either of these cars against a C4, but I've got loads of other SCX cars and on my predominately Scalextric Sport rally track, which is mainly R1 and R2 with the longest straight only 2mtrs, the MSC cars are among the slowest because they are very hard to keep in the slot.
The detail on the cars is brilliant, but I'm unlikely to buy any more, and if I'd have paid the normal asking price for them I'd have been very disappointed. Detail is all very well, but handling is of greater importance to me.
In fact, I'm having problems with the rear axle on the 6R4. I can't get the crown to grip the axle. The grub screw has been tightened that many times the the allen key now spins in the screw and the crown is still loose . I'll have to get a better crown.

The belt driven 4wd was never the brightest of ideas, either. For the band to be tight enough to actually drive the front wheels of my MSC cars when they are under load, the front axle is pulled out of line.

To sum my feelings up.......... Buyer beware!
Just my 2p.