How to get a few more Hp

My buddy (and first tune attempt) has a 98 Firebird with an LS1, 3600 rpm stall, according to the dyno, GM "Hot cam" headers and exhaust. After tuning, we get about 319 rwhp. Doing the math puts him somewhere around 380-390 flywheel hp. He want to get to the majical 400 hp without spending too much money.

Can we just port his factory intake to gain a few HP, and if so, how much?

Any other easy mods to do to this thing? Porting the TB maybe?

When accelerating in 1st gear, you have to be rolling 10+mph or you don't have any traction. Once it catches, revs then barks second, the engine seems to bog like it is in too high of a gear. I think he has 3:43 gears. Any help on that one?

I have a dyno run captured if anyone can help or look at it, but I don't know how to load a log file.

Thanks.

Dont waste your time on the LS1 intake, they are garbage.. Look for a used LS6 intake, you can see those for around ~300 or so.