If the long block is all stock I don't think it would help much at all. And at that your tune would need to be adjusted. And... the larger a MAF the more problems you'll have getting the idle dialed in.
On my 06 I've founf that the air filter setup is definately worth a solid 10-12 HP & TQ.
It's something small.. but you can shave down the TB rod and bolts. Maybe even knife edge the blade. The TB is the smallest crossestional (or choking) point in the whole intake. Opening it up will only help high rpm power.
He who is enslaved to the compass is free to sail the seas