Just an update as how reliable this swap was and the performance point of view driving it to vintage and at RTT 2012.
Driving down to vintage, we were 4 cars, (2) M5s, (1) 525i-S54 and 1M coupe. We were cursing about average 75 to 85 miles/h and no problem and few times I had it north of 140 m/h to just test the stability and braking among other things checking the A/C which was on most of the time (works great), and gages, cluster, and other electrical and electronic which all works as I hoped it would. At the same time, we were driving on the twisty back reads of Smoky Mountains which was great testing ground for suspension and power shake down that was performed flawlessly. On the other hand, I had my eye on the oil level till the end of the trip, and it was fine, so as the 6 speed operation, shifting gears just feels like butter and as for the rear end 3:73 combination with 6 speeds and the S54 gives you the feeling of unlimited pull.
Over all the swap was successful and performance is out standing and extremely pleasurable and highly addictive. Thanks to Stance Factory!