there are two oxygen sensors. The sensors runs between 90-110 for OEM fit, the wire harness can pre-fab/wired. It is a safer bet for repairs.
Deducting $200/tax for oxygen sensors (up and down stream) or with the mark up, it leaves $100.00 for labor/or $120 without markup
The down stream sensor seems to easier to replace than the up stream sensor if you have a lift. The total time to do it on your own is about 1 and 1/2 hours, or 2 1/2 hours (slowly).
The engine will most likely be ruined.
Unlikely. Could be as simple as a loose gas cap. Considering that the emissions warranty is still in effect, take it to a dealer.
2003 TLS, first transmission replaced at 35000 miles, second at 90.,000.
30% of 35,000 = 30% * 35000 = 0.3 * 35000 = 10,500
35% of 35000= 35% * 35000= 0.35 * 35000= 12,250
3% of 35,000 = 3% * 35000 = 0.03 * 35000 = 1,050
6% of 35,000= 6% * 35000= 0.06 * 35000= 2,100
20% of 35000 is 7000 20% off 35000 is 28000
5% of $35,000= 5% * 35000= 0.05 * 35000= $1,750.00
35 liter = 35 x 1000 = 35000 ml and 35000 ml is 35000 ml, you decide
700x5 is 3500, x10 is 35000, 35000 x1 is 35000
390000 - 35000 = 355000