Hmmmm...
This kind of reminds me of some liquid intercooler posts. The question is not how fast you can go with a 3 bolt, the question is wether or not there is any gain by going to one.
I say go to a 4 bolt housing, get the waste gate tapped in before the turbo, and put a wet NOS kit on the car with a hobbs switch. I have a whopping $160 in my used NOS kit. Its jetted for only 50hp. With the 50 hit my stock long block spooled my P-trim T63E, 3200 art carr combo the way your built motor spooled my T66 dual ball bearing. Get the NOS kit and find out what HP level you have to jet it to to get the spool up your looking for. Have the set up wired through a hobbs switch AND a throttle switch. Have the hobbs switch shut off the NOS in the 15 to 20 pound range and the throttle switch to kill it if you let off the gas. This is easy to do properly with a relay, using the hobbs and throttle switchs as part of a "holding circuit". Wiring it up this way will not allow the NOS to kick on and off.
Just think: 100 hit of nos, 15# t-brake launch, you'll be able to look Cliff in the eyes with your head lights. hehe
Jason