I'm pretty certain based on some work I did last year that the sensors on the TBs (L36 and L67) are all 100% identical. One of the mods I did for my Monte was a L67 TB on a L36. I port matched the exit of it to be much like the L36 TB and the mating surface on the L36 UIM. I also chose to use a '97-'99 TB since that had the MAF bridge (easier to port the inlet, I've read issues using a '00-current, as the MAF hump is a pain to port). The only diff with the MAF that I know of was to get my '04 MAF to fit in my donor '97 L67 TB, I had to port the MAF hole once I got rid of the bridge. My donor had all sensors BUT the MAF. But like I mentioned, the part stores list the same MAF for L36 and L67 (year is the only thing that changes the number). I don't know much about PCM programming, but as I understand, there is not much difference (heck, I was told by a few more knowledgeable people, if I used a '00+ L67 TB and just matched the outlet and did NOT port in the inlet, since it's the same inlet as the L36, the MAF data stays the same).

Here's a write up in detail on what I did:
'04 Monte Carlo SS - L67 Throttle Body

Here's a '00+ TB inlet:


Here's a '97-'99 TB inlet:

 

But in stock form, especially if you plan to run an external MAF like the 85mm, the 99+ is the better TB to go with. With a turbo setup, I don't even know if it's really worth the time and effort to go through porting it out anyways, since its going to be pressurized anyways. Obviously there would be some minor gains, but not as drastic as on an NA or SC setup.

 

In stock form, I'm not really sure which version is the best (comes down to which is best, having the MAF hump or bridge). Since I wanted to open mine all up in a N/A setup, the bridge made the most sense, from there, cut that sucker out.

I don't know enough about turbo builds, but I'd imagine you're right, due to the pressure or volume/density of air created by the turbo, not sure a ported inlet matters much. That's research beyond my current needs

I would have done for a ZZP HV throttle body, but I felt the L67 route was a little better for me cost wise (as I understand, my current setup is similar to a Stage 2 ZZP HV TB). It cost me the donor part and time to make my modifications (and gave me a reason to use my Dremel and buy more bits for it).