I'm looking at messing with my a3 head a little bit (maybe a full swap ) when It gets a bit warmer

Just wondering if there will be a significant difference in numbers between swapping a full a2 head in vs just the a2 cam's with a vtec killer set up?

This car is going to be my summer DD so obviously a full a2 head swap would be way more reliable and way better on gas compared to a vtec killer set up... BUT I have heard that you can fix the idle on a killer set up as well with a good tune? Not sure so I just want to get all the opinions I can. :D
Or a good link to a thread that already compares both haha.

Thanks in advance for the help :D