Good observation about the tire size from stock, hence why it was asked if you can lock the brakes up. On most all cars that are stock you can easily lock the tires with the stock brakes. Even on upgraded rubber you can as well. When you upgrade to the point that you are at, it may be time to try a "premium" rotor, which everyone should use anyways and a more aggressive pad.
As far as feel goes, you need to do what Patterson said and make sure the booster is getting adequate vacuum that it is supposed to get since your swap.
You could arguably get braided steel brake hoses, which help in the "feel" department since they don't flex like the rubber ones due when applying brake force.
Remember there are a lot of opinions and directions to go depending on what you want to do. Obviously SAFETY is #1, if you coil overs are rattling/leaking (ahem like mine are ahem), I would seriously consider making a repair there first.