Id have to see a time slip from Bonneville or at least a video of a GPS along with the tach & speedo.
From the mods mentioned above, I'd say around 160 - 165 might be possible in a N/A with the EuroCharged tune, don't know about the IM tune.
The 2 plugs per cylinder is OEM, the colder heat range and Magnecore wires are little if no HP gain.
You also gain little with any exhaust mods.

Most that have done the dual CAI ( or single CAI ) with 74mm TB and EC tune have seen around 30-40 CRANKSHAFT total gain, probably @ 10-15 at the wheels.
I haven't seen any figures on results of an S430 injector swap, I hardly think that necessary on an N/A.

Also, there has been debate on the "stock 220 ( actually Chrysler said 215 )"
Many believe this was a marketing strategy by Daimler/Chrysler at the time to keep the MB S320 sales from taking a hit, and many think the true OEM HP for the N/A with the 68mm TB was @ 235.
Perhaps someone has posted a dyno for a NEW stock N/A, but I haven't seen one.

These are just my thoughts on the subject, I'm sure others will take issue with some, if not all, of my statements - I won't be offended.