Need to replace my O2 sensor and was wondering where I should buy it from. Should I spend my money and get it from the dealer, or should I buy it from a Pepboys type of place? I'm just wondering if it matters if it is original equipment or not.

98 SVT
Black w/ Midnight Blue
Stock Rims
Sparco Pedals
Removed Resonator
TH Fix
Superwhite Bulbs
B&M Shifter
K&N Filter
KVR Cross-drilled rotors (front)
KVR Pads (front/back)
Aeroquip Steel brake lines (front)
#4248 of 6535 built
15.574 @ 88.35mph
15.814 @ 86.62mph