Forced Induction Vortech V3 Si vs V1 Ti Supercharger

I am considering a V3 Si tuner kit with Heritage series gears while prices are good over the holidays. However, I am wondering if I should consider a V1 Ti tuner kit?
I have a stock bottom end 302 with TW 170 heads, Lunati 20350711 cam (221/229 @ .050 .540+ lift), TMOSS ported GT40 intake setup, 70 mm TB. 3550 5 speed, 3.55 gears.
I may consider an engine upgrade to 347/363 (Dart block based) or even a 351w at some point, but could be a couple of years, or maybe never if the SC and 302 keeps me happy. This is a 100% street driven 1990 Foxbody convertible, maybe 1000 miles per year.
Of course a larger engine would be served better with the Ti trim, but until then or if I end up staying 302/306, which would be more efficient in the 8 to 10 psi (maybe 12 psi) area? I realize a Dart based motor could take a lot more, but then there goes the drivetrain upgrades. 12 PSI via a Si trim on a 363 would be some serious power (to me anyway). When would the lack of efficiency on the Si and heat start to become an issue?
Would the Si be better on a 302 in the lower PSI and rpm ranges? 5800 to 6000 RPM would be my limit.
I appreciate any advice on this.

John Dirks Jr said:

Was your stock bottom end 302 block decked when those heads were put on? If not there's a fairly good likelihood you'll have head gasket problems when you boost it. I went through it myself. Just a heads up. Seriously, on my stock 302 block, removed was .002 on one side and .001 on the other. It was not until I had the block shaved that I could hold cylinder pressure under boost. The GT40 heads had been milled all along and that wasn't enough by itself. Milled heads, decked block, Cometic mls gaskets, ARP studs......no more problems.

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No, it was not decked but I am using ARP studs.
What kind of boost were you running when you had such issues?