More of a science, as in third degree polynomial...
This was a very crude scatterplot (no filtering) of laminar flow test across an LS6 MAF, notice the trend line...
http://img26.imageshack.us/img26/3100/rawmafdata.gif
You can make the 325I faster, for cheaper.
Exhaust Manifold Turbo Engine Mount Head Studs MLS (Headgasket) Tune People have made 600+whp on this basic lay out. Obviouslly there are more parts needed to complete the system, but its certainly doable.
Orrrrrrrrrrrrrrrr hit it with a 150 shot and rock ~325whp.
Orrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrrr find a L67/L32 lower end, add some head studs, and make 400-500whp with a T61
I've read some of the CheyTac boys getting in the .408 & .410 3,500-4,000fps range on the 300gr rounds...but thats a very exclusive group. I'm in pain just thinking about what that round does @ target.