High compression pistons/cam upgrades - expected hp gains?

[90gs]

how much hp should i expect to gain from raising my compression ratio from 9.2:1 to 10.5:1 (max for 91 octane gas right?). i heard that every .5:1 you raise your compression ratio you'll gain about 10 hp. that means i'd gain 26hp from going 9.2:1 to 10.5:1.. that sounds a little high...

how much hp should i expect from some skunk2 stage 1 camshafts?
what about stage 2 camshafts? on their site it says you need drivetrain upgrades to run stage2 camshafts, does that mean like an upgraded clutch and flywheel (planning on doing that anyway) or does that mean like a limited slip differential?

and finally, how much hp should i expect from some skunk2 adjustable cam gears at 0' advance/retard? (i was going to get aem but i keep hearing that ppls timing belts snap on them with the aem cam gears)

[99GSR]

The skunk2 stage 1 cams will give you about 10-15 HP. I have them on my gsr and they shaved about .7 off my 1/4 e.t. for stage 2 cams you need to upgrade your valvetrain not your drivetrain you'll need to buy dual valve springs and titanium retainers wich give you about 1,000 more RPM.