Not sure about the smog portion (CA is funny about stuff). Everything I've read though, indicates that the swap isn't even worth doing. You buy the intake, spend another $300-$600 on an out-of-the-box tune and get what for it? You get a couple more horses up top at the expense of torque at the bottom. Not bad for $900+
Supposedly, there are two things going on with the whole 302 upgrade. 1- Cold-air intake and SCT tune, which seems to add about 20-30 hp and 20-30 tq with 93 octane gas; 2- the actual 302 intake manifold seems to add an addition 10HP to the tune while reducing torque back to stock numbers AND maintains peak HP and peak torque from 6500 to 7500 RPMs, which is quite a big deal if you are racing someone with top-end power. Essentially, you are gaining 40 horsepower AND your power band is extended a bit (remember stock 5.0 GT redlines at 7000). In theory, the Boss 302 guys are paying 10-20k more for a $1000 tune.
The REAL proof would be to see two equally great drivers race a stock GT 5.0 versus a GT 5.0 with the SCT tune, 302 intake manifold, and a CAI. There should be about a half a second difference in 1/4 mile; that is pretty substantial for $1000 if all the number juggling is true.