If you have a high boost S/C, why not take advantage of it? If you read through all the old CTSC posts, almost every driver loves the newfound power right away but then finds out that 330rwhp is not REALLY enough.
Why go to all the trouble if so many before you have felt a little "disappointed"? I say, go for the high boost right away. You will pull out an additional 40hp/Tq with a conservative tune and that should get you over 380rwhp without any real additional risk.
Good luck with whatever you decide.
To be honest seat of the pants the HiBoost does not really add that much overall. You end up with a slightly higher peak HP about 10 lbs more TQ through the middle and even hotter than the normal hot IAT's that the CTSC offers. I did it on my '91 and I tracked it.
The biggest issue is and always will be IAT's with the CTSC design, you may get to 370-380 whp on a dyno but put the car on a track by lap 3 you will end up making 320-330 whp after it heat soaks and the ECU pulls timing. On the street you get to play a little longer but a 1-2-3 gear pull will put the IAT's in the 190-210 degree range and the car will just pull timing and add fuel and you will loose power.
Heat is the cause of most engine stress, so if you can cool the charge temps down to 120-140 range and keep oil temps under control less than 250, the 3.2l with a good tune will last a very long time. The 3.2l are more expensive to rebuild and will require either a new block or sleeves so it is best to take caution in your search for more power.
Dave