Hey, first post and I'm no expert so please be gentle!

Basically, my car (2007 Jetta 2.0 turbo petrol, 147kW, engine code BWA708699) has been misfiring, surging and stuttering intermittently so I scanned it and got code P0135 - 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1) - i.e. the pre-cat oxygen sensor - which was odd because I've never put anything but premium 98 in it. Maybe the previous owners weren't as kind.

Anyway, i was quoted $560 for a replacement sensor and $200+ labour, which I thought was pretty steep given it's a fairly standard fix and the part can be bought for about half the price online.

So I guess I have two questions:

1) I'm not 100% sure of which part to get. I keep seeing what appears to be the correct part - 7/08 2.0L Turbo 4cyl pre-cat 4 wires - however it's stating engine code as CAWB, not BWA. Will this part still work the same, or do I need to find a BWA specific part? Not entirely sure what the difference between a CAWB and BWA engine would be, or how it would affect the 02 sensor. I have seen BWA sensors, however they state 9/05, not 7/08. So again, not sure of the difference.

2) The part I keep seeing online for closer to $240 is a Walker part - so not OEM, but generally a decent brand. Should I even consider this or should I keep looking for a Bosch part (which I haven't been able to find online yet)?

Any advice would be really appreciated.

FYI the parts I'm referring to above are these:

Volkswagen Oxygen Sensor - Jetta

http://www.ebay.com.au/itm/OXYGEN-SENSOR-O2-VOLKSWAGEN-Jetta-7-08-on-2-0L-Turbo-4CYL-PRE-CAT-4-WIRES-ENGIN-/400553633945?pt=AU_Car_Parts_Accessories&hash=item 5d42db6899&_uhb=1


Cheers guys.