That one is not California compliant as the OP requires for his state. And Mass. WILL ding him during their smog test since the correct cat must be there to keep the Check Engine circuit and light happy which is required by the OBDII system.
I paid less than $100 for my Calif. compliant cat from www.car-sound.com/
. I had to call them since they don't show Jeep in their drop-down list of vehicles they have cats for. You do have to make sure it has the bung (mounting port) for the 02 sensor which screws into the cat itself. eBay also has cheap Calif. compliant cats too, I'd check there first.
Here's one that has the required 02 sensor bung required by California but it doesn't specifically say it is California compliant... maybe they just left that out of their description but double-check with them. http://cgi.ebay.com/ebaymotors/97-98-99-00-Jeep-Wrangler-Catalytic-Converter-OEM-NEW_W0QQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247 QQcategoryZ33629QQihZ009QQitemZ190067343330QQrdZ1Q QsspagenameZWD1V