Well, we have a guy here who has a modded Series I who has gone well over 140 (oops was typing this and Will beat me to this part). I believe there is someone here who has taken a ungoverned Series II L67 out for a high speed run, but I can't remember who it was or what they ran.
I'd be willing to bet that with the mods you have listed you should probably be able to hit 150+, but I honestly wouldn't suggest trying too, at least not on a public road. I have been pretty crazy (hit around 157-160 in my Lebaron Conv with the top down
and have had my 1994 SLE up in the 120'*, and had the SSEi up to 131 before the governor kicked in). The Lebaron run was shear stupidity and the other'* were had high risk factors too, but weren't quite as wild. But as has been said before, the farther you go past 100 mph the more your cars handling and braking responses drop more quckly. At 140+ I'd say you're practically just a speeding bullet -it'* only one way and no-little slowing down until you hit something.