Ok, the wideband is installed in a separate bung welded just before the cat. This way, I can run the stock ECU if there are any issues with the MS.
Building upon the MSPNP pro base map, I was able to get the car to idle fairly well. It idles at around 850 rpm and is as stable as it idles with the stock ECU. I am currently running it at around 13.5-14 AFR at idle with around 30kPa MAP. A/C idle up works very well. I can turn the A/C at it's highest setting plus all other stuff like the headlights, wipers etc. without stalling the car at idle.
I also did a couple of short drives and the car drove fine. It is slightly sluggish than the stock ECU but that is expected as I have not done any significant amount of tuning. AFR stays around 14 to 15.5 most of the times but it does drop to between 11.5 and 12 under hard acceleration.
The car takes a bit longer to start and I have to pump the gas pedal once or twice while cranking to get it started, but after that it idles and runs without any hiccups.
Overall, I am very happy with how things have started and I guess the actual fun starts now.
One issue I have is that MS is not reading my vehicle speed sensor. I am feeding the VSS to 'Nitrous In' input of MS3x and I got the attached settings from somewhere in this forum. I would appreciate if someone could cross-check the attached VSS settings for any wrong values. The VSS column has zeros in the log, so these settings are not working at all. Perhaps, the input type should be Analog.