LOL. You guys are cracking me up. I really appreciate the feedback and everyone's time is valuable. And tknj99, ha, I actually am a CEO. I'm an older dog that just wanted to buy a car that was fun to drive and tinker with again. I just want it to be at least as fast as my old CLK550.
I have been doing a lot of research on this subject and it seems to always come back to being able to use your warranty vs not. Performance wise it seems that they are very comparable, but if you are adamant on the exact performance level I don't think anyone can help you other than you doing a comparison of different results that you can find on the various forums for the two different options.
With the JB4 I don't think there is a record of anyone being flagged "TD1" by dealers, so as far as I can tell you will be able to get warranty repairs for engine components done if something happens during your warranty period. Just keep in mind that you will also have to remove the unit when going for service, so this might be a factor if you use the dealer for all regular maintenance and don't want to have to remove and reinstall the unit every time you bring it in. It is approximated as a 30ish minute install/removal but depending on how savvy you are (or apparently how big your arms are) it can be done in a matter of minutes or hours. So it all depends on what your tolerance is with these things and having warranty work denied and paying out of pocket.
Performance wise there are so many different results for the options that it is really difficult to give exact numbers. Also, the way APR and BMS market their product is very different so I wouldn't just go on what is advertised. I don't know much about various APR dealers and their customer service but from my in depth reading of the various threads here, I can say without a doubt that George at BMS offers the highest level of customer service. I'm not even a customer and I can say that with confidence.. He is very active on the forums here as well...
Just a few thoughts.. I am by no means an expert and don't have any experience with either so take all this with a grain of salt obviously. I have just read a lot lately so thought I would share my interpretation of this.