high flow cat/o2 sensor

Fround out I need an O2 Sensor and a catylityc converter for my car in order for it to pass emissions. I was looking online, because the mechanic is a ripoff, so first of all, i need to know if these things are hard to dinstall by yourself.....and also if i can get some reccomendations for good ones to buy. I waslooking at this one RANDOM TECHNOLOGY 92-5 CIVIC HIGH FLOW CAT for 250$.....I have a 95 civic coupe EX....thanks!

usually it's an easy install, unless you had your aftermarket exhuast either welded to the cat, or in place of the cat. if not, there will be two flanges that you'd need to unbolt and bolt the new cat in. if it has been modded like that take it to your local muffler shop and have them do it. MAKE SURE WHAT YOU'RE GETTING IS NOT A TEST PIPE. people sell test pipes on ebay that say "high flow cat for blah blah blah" they are illegal and you will not pass emissions with one. your best bet, put a stock replacement cat on there and take it off when you're done testing.

I just got a new O2 sensor a couple of weeks ago. It's a bitch to unscrew. The guy who swapped my engine said that the "check engine" light would come off once I get the new sensor. However, the light is still on. I unplugged the battery cable while putting on the new sensor. The sensor isn't one of thoe universal ones, but I did pay only 70 bucks for it, it was brand new. How do I know if the sensor is working properly? I got new plugs and cables also. Emission test is coming up next month. Does anyone have any suggestions on how to make sure the sensor is working properly?

damn, what state do you live in that is so strict, i have Texas. the 5 minute inspection.