I have a 2001 WS6 TA with SLP lid and MAF. Love the car. My problem is, once in a blue moon if I'm driving between 50 to 70 on the average, and then if I put the peddle to the floor, the car acts like it don't shift down, or mostly to describe it, boges down and maintains the speed for a few seconds, then it takes off like a bat out of hell like it should. This problem does not occur every time. I have changed the plugs and wires, trans and rear fluid to see if it would change, it didn't. I've had the timing checked and it's where it should be. I also checked for any codes that may pop up and nothing. I think it might be fuel pump, but it's just a guess. Only happens between 50 to 70. Tried it at lower and higher speeds and it won't do it.  

auto trans?  

Auto trans it is. I forgot to mention, it's a versus deal, sometimes with the bogging down, it might rev as if I had it in neutral and was giving it gas, reving up and down then bog down, then take off. Sometimes it does the reving but not all the time, mostly just the bogging.  

Sounds like a tranny issue, which is electronic. That may explain why you don't show a code in your OBDII. I believe (somebody correct me if I'm wrong) it has it's own computer that interacts with the ECM. I would start with the easy stuff like checking for loose/damaged/dirty connections with the harness. I got a feelin, based on your description: "revving like it's in neutral" you may need to get chummy with your local tranny guy.