The probe is small enough it will never create a disturbance coming out of your J pipe. The real tuning of your 2t exhaust is by sound and not flow at any rate. Sonic tuning. You want to place the probe 6 inches from the outlet, otherwise you will get a bad reading. Too close and you will burn it out. Ive run them as far as 3 feet from a rotary and still got perfect results, but rotaries can max out over 1700 F and anything closer than 1 1/2' will burn up in a few runs around the track. Same with A/F meters, those need to be pretty close as well. There has been several cheap Stoichmetric meters on ebay lately also. You can use any O2, 0-6v 6v-0v etc, that is the same voltage as them and it will work. Majority of 1 wire O2s are around 30$ A/F gauge cheap is 5-10$
Next time I go out to my friends Ill take a pic of his elite, its got a trailtech vapor, EGT, A/F, Voltage, Fuel level, and a huge 6 inch tach. Theres a way to install analog tachs on our scoots also if you didnt already know. Riding his scoot is like driving an Auto cross car I swear. So much to look at.