The '88 is an OBD I system, most OBD I only have O2 sensor(s) on the exhaust manifold, or "Y" pipe, so only pre-Cat(upstream).
OBD II is when they added an O2 after the Cat to monitor it's ability to reduce HC in exhaust.
And as stated by previous posters, removing the Cat is a bad idea, unless it is collapsed, then you should replace it.
Exhaust systems are often misunderstood, people see racing cars with straight exhaust systems, no muffler or Cat, and think that just removing these will increase performance.
That is untrue.
Those are TUNED EXHAUSTS, the pipe size and length FOR EACH CYLINDER is calculated to give the correct amount of backpressure(yes, back pressure is GOOD
), for the power band they want, low, mid or high range.
Your current exhaust system has been calculated to give the best performance in the mid-range power band, WITH Cat and muffler, assuming both are in good condition.
Some change to headers and if they are the correct ones for the engine you can move the power band lower or higher, no increase in power it just moves it to a lower RPM or higher RPM, that's the point of headers
EGR system doesn't "rob" power, it actually helps to keep cylinders from pinging under heavy loads, so increases power by preventing pre-ignition.