Put the EGR back together right away. You're probably thinking "But putting exhaust gases back into the intake is a bad thing" and you'd be right BUT the fuel mapping programmed into the computer accounts for that exhaust gas displacing oxygen in the combustion chamber and fuels accordingly. Without EGR, what would otherwise be unreactive exhaust gases is now fresh air instead. Extra fuel would need to be added to go with the extra air. The system can compensate over time(to a point), but you still run the risk of going lean while the engine is cold and at wide open throttle when the system is not reading the oxygen sensors. Add this risk plus the extra ignition lead and you've got yourself a recipe for ventilated pistons.
1 and 2 on your list are the only things worth doing if you want more mojo. Bear in mind you will have to run the highest octane available at the pump. 91 to 93 depending on your location (dont get crazy and buy race gas, it contains lead and will wreck the oxygen sensors)
One thing that you dont hear much about is the cam sensor inside the distributor - it controls fuel timing and when you turn the distributor, you are also advancing the injector timing. I dont know if a few degrees makes a difference in the fueling but my motor seems happiest at about 12 or 13... You will notice a big difference going from 10 to 12 but after that, the 'law of diminishing returns' sets in and adding more doesnt help all that much. Remember that when you advance the distributor, you are adding 2 degrees of lead to the entire advance curve which is preprogrammed into the computer. You can't modify it at all. There is a point around 44mph in 4th gear where the computer is adding the most ignition lead. It's around 50degrees total advance which is damn near unheard of in the performance world but they did this to make the archaic engine design pass ever stricter emissions and mileage standards. The point is, whatever you add to the distributor is applied at this ~50 degree advance which is already pushing the limits by itself. Everywhere else besides this high advance cruise condition is improved though. So listen carefully for any sort of metallic 'pinging' sounds coming from the engine in 4th gear cruise.
I dont recommend gutting the converter for 2 reasons: A) once you put an aftermarket muffler on there (flowmaster especially), it sounds like ****ing hell when you get on it. Like fire crackers going off in the trunk. I found this out the hard way. :thumbsup: Nobody talks about it, but the cat has a large effect on the sound.
And B) You wont find it written on ANY aftermarket muffler package EVER, but simply put, back-pressure is good for torque.:shhh: When you reduce backpressure, you essentially move your engine's 'torque peak' to a higher point in the rpm band. In a street driver, your peak torque ends up at an rpm that your engine will rarely ever see in daily driving. These motors dont rev high, and they dont flow much to begin with, so increasing the exhaust system's flow capabilities will not net you much hp. In my opinion, the only reason you see a benefit from a performance muffler on these cars is because they were designed to be quiet as number one priority. Notice just how big and heavy the stock muffler is....
In your case, since you already gutted the cat, I dont recommend changing that muffler but if you must do it, try to get one that contains both baffles and fiberglass packing. This will help suppress the awful banging that you will hear through a chambered muffler such as a Flowmaster. In my case, I first added the flowmaster 80 series and the sound was nice and smooth with a good low rumble to it but then I got greedy and gutted the cat and all hell broke loose. Performance also dropped through the floor. My remedy was to replace the cat with a 1 3/4(backpressure!) magnaflow glass pack.
For the same reason as mentioned in the exhaust system, doing anything to the intake will net you zip. The motor itself cannot out-flow the stock intake.
A TB spacer will do nothing also, mostly because the engine is multiport fueled rather than throttle body injected. Adding length to the intake tract is only beneficial if it is done for each individual cylinder rather than the entire shared manifold volume. See the Allante's 4.5L - that's how it's done!
The irony is that on these cars, the most noticeable increase in power that you can have is the one that costs $0.00