I swapped suspensions between cars, and I have a brand new 19mm master cylinder and found that the silver car has a brand new 17mm master cylinder. Brakes are stock, metal master pads.

I know that the 19mm will not improve braking performance, and will have a shorter pedal travel (along with more effort) than the 17mm.

That said, if you had either to choose from with stock brakes - what would you choose?

It's a feel issue. Some like one, some like the other. There's no right answer here. If you like the brakes as they are, leave them alone. If you want a firmer pedal, try the 19mm unit. All it takes is some time and brake fluid to do a swap.

Damn, an answer that I figured I would hear. I guess I will shoot with the 19mm for giggles.

If the 19mm has not been used, then put it away for a while until it is needed. Otherwise, I reccommend the 19mm.