I haven;t read all replies, but I was going to suggest the same that
@pjtoledo did. The problem with any upgrade ont he front of your truck is going to be the 15" wheels, not much bigger than stock brakes will fit in that size. Sport Trac may be an option if they wil fit your wheels or you are willing to move up to a 16" wheel. In years past people have devised ways to install 13" rotors and calipers from a Mustang, but those require 17" wheels. I'm also not aware of anyone currently making the 13" kits for the later model (98+) trucks.
I'm of the opinion that the only thing you will gain from drilled and slotted rotors is faster brake pad wear. If you have bad braking habits and tend to glaze the pads slotted rotors will remove the glaze (along with additional pad material) every time you press the brake pedal. There is also the issue of drilled and slotted rotors being more prone to cracking, it vastly depends on quality of the rotor and how the holes/slots are made. Keep in mind that most of those cheap D&S rotors started life as cheap "ChingChong" plain rotors that were weren't known for their quality in the first place, then that same "ChingChong" assmebly line started drilling holes and cutting slots. You're looking for better quality brakes, do you really want to take cheap rotors then drill holes and cut slots in them as an upgrade?
A lot of experienced people in the automotive industry have voiced opinions on this and feel that a good quality plain rotor with high quality pads is the best option. There are placed where a quality drilled and slotted rotor can be beneficial, but it's generally in extreme duty on a track. Brakes on race cars aren't known for longevity, nor is that trait high on their list of concerns. They are primarily concerned about best braking performance for the span of a race.
If the Sport Trac brakes are not a possibility for you, or possibly in addition to them, I think your best gains would come from a set of good quality plain rotors. Put the money saved on cross drilling and slotting to put towards a set of high performance brake pads from someplace like Hawk Performance or EBC.
Well that's 1¢ on the front brakes. If you put it with what I say about the rear brakes below, you'll almost have 2¢.
For the rear... As noted, if you already have the 10" drums in the rear you have about the best you can get without converting to disc. If you convert to disc there are three basic options as I see it:
- Convert existing axle to disc with mustang parts
- Swap to Explorer axle
- Swap in '10-'11 Ranger axle
Some will debate if these options are even better than the drums. I would tend to think that atleast the Explorer brakes would be. The Ranger brakes should be as well, but the main driving factor behind them was federal mandates for traction/stability control, not improved stopping performance.
If these swaps/conversions are worth the price of admission is something you have to decide. Keep in mind that a large majority of the braking in a truck comes from the front brakes.
The Cobra rotor was one inch larger and vented compared to the 10" solid rotor on the V6/GT cars. They all used the same caliper, but the Cobra used different bracket and thinner pads to accomidate the larger rotor.