I have a PLX m250 for sale, ill let it go for 100.00 and all u need is the gauge that cost 50.00.

I use my wideband to datalog and check my A/F ratio all the time.i rather be safe then sorry. There is things that can change a tune and make you run crappy, such as a hotter day will make you run more lean and a cold day will make you run richer.