The TXS TBE should not make your car run lean. It is only going to let you turbo spool a little faster. The A/F ratio so to speak will not be changed. To start leaning out your car you have to increase timing or size of turbo, etc.

Good luck!!!

 

the reduced backpressure will allow your car to boost a little higher at peak then settle back to what your ECU is after... this wont cause you any issues.. now if you get an MBC and crank up the boost you will be to lean and will need more fuel.