Pulley size should not be put on a pedestal as much as it is sometimes. Most guys running well built cars will hardly ever run pulleys below a 3.0 on the street, but at the track with some race fuel and constant scanning, they drop sizes and thats what they list in their posts after a race and thats what you guys see. You will never be able to run much smaller than a 3.2 without some good tuning on a cammed/intercooled car. Non-intercooled it would be more like the 3.4" area. It doesn't take a 3.0 or below pulley to run 12's.
The cometic head gaskets are very good, they just require a good install process like the other headgaskets do, but the 4 layers need to be separated and sprayed with copper spray before being put on the head. Prep and install procedure is key. The gm gaskets will hold up well untouched from the factory, and i believe paul jerkatis (PRJ) swears by a certain type of the GM gaskets on a whipple build he is helping with that will see a lot of boost and some higher cylinder temperatures. But on a xp/intercooled car most gaskets should hold up fine as long as the install is done properly. I would just think about ARP head bolts.
The springs/ timing chain will depend on the cam. Most people have tried to stay away from comp cams springs due to a lot of failures on the 105's and also higher rate springs. A few local installs have been running 105# springs with new stock timing chain with a s1x cams with no ill effects, one low 12 sec genV car and a high 12 regal, non intercooled. If you get a double roller, make sure to stay away from the JP set and also get the crank gear milled to match your stock crank gear.
