You can delete EGR, but you will need to tine the PCM to keep the SES light from illuminating.
You could also quite easily weld an EGR bung onto the drivers side primary tube and retain EGR.
I noticed a drop in fuel economy when I disabled EGR.
I installed my O2 sensors in the headpipes just after the collectors of teh headers. that way I idnt have to disturb the cermaic coating of my headers.
Be prepared to buy some O2 sensor wiring extensions. I wish I would have done so on my truck. Whatever you do, dont lenthen the O2 sesnor pigtails themselves, always lengthen the wiring hraness on teh truck. Cutting and splicing the O2 sensor wires themselves will cause errouneous O2 sensor readings.