[95camaro5spd]

hi everyone. This is my first post here, and i have some questions about my vehicle.

The car is a 1995 chevy camaro 3.4l 5spd. Everything in the car is stock. The car has close to 200,000 on the engine, and its time for the still stock catalytic converter to go. I was talking to my local mechanic, and he suggested purchasing a "test pipe" from autozone and to replace my converter. since my states emission laws dictate 1996 and newer to be tested for emmisions, this sounded like a good idea to me. Are there any risks/problems with this idea? Id rather this than purchasing a hi-flow cat, since it seems much cheeper. Also, I was wondering how the converter is concected to the exhaust on a stock 95? Is it bolted on, welded, or does it need to be cut off. what impact on my cars overall performance would removing it provide?

Also, its about time to replace the spark plugs on it. I know this is no major decision, but i was thinking about going with bosch double plattnums. Since I put bosch platinums in my winter rat and they seem to work fine. Does anyone have any different suggestions on a spark plug or are these a good choice?

Aside from that, i had my car pluged into the computer at advanced auto parts to see if anything was wrong with my car and my EGR valve came back bad. All 3 cyclinders on the egr have failed, and a new egr is ~170 bucks. I know the EGR valve has to do with the reburning of excess fuel (i think ) what impact on my cars overall performance/fuel economy would a new egr valve have, and should i still get one peding i remove the converter?

Lastly, since i purchased the vehicly last fall with 188,000 miles on it, i have run nothing but 93 octane gas in it. I know my small engine does not necessitate it, and i am far from a fuel expert, but i have always been under the impression that higher octane gases are more filtered and burn cleaner. Is this true, or am i just wasting money? Am I seing any benefit by puting higher octane in my car, or am i negatively impacting it? one person i talked to said that since i have a smaller efi engine, the excess additivs in the higher octane gas are just building up in my exhaust and actualy hindering my performance.

Could someone please set me straight on any of these?