205/65/15 tires are OEM standard on 15'' (6'' wide) alloy wheels on Solaras.
205/65/15 tires are usually safe to mount on rims width between 5.5''-7.5'' (best in middle of range)
you can fix the flex pipe at any local "muffler workshop", around here it costs about $140 to have the old piece cut out and new piece welded in.
you need the new heated o2 sensor, the fault is not with sensor reading range, it's the heater circuit at fault, usually the sensor itself is bad when that code is present. replace it with Denso unit (OE style for easy plug and play application), check your part number here and then shop for it on ebay or amazon:
http://www.densoaftermarket.com/cata....php?part=o2sn