Motorcycle Repair: Screamin Eagle® Stage I Kit for EFI Models, screamin eagle exhaust, harley catalog

Question
GREETINGS FROM THE OTHER SIDE OF LAKE ERIE!

I OWN A 03 FLHRCI [18000 KM] W/Screamin' Eagle EXHAUST SLIP-ONS/DEALER INSTALLED

I'M NOT SURE IF CALIBRATION WAS PERFORMED

I AM INTERESTED IN INSTALLING THE Screamin' Eagle® Stage I Kit for EFI Models
SEEMS TO BE A HIGH-FLOW TYPE OF KIT

LOOKING AT THE PARTS IN THE HARLEY CATALOG
THERE ISN'T MUCH THERE FOR MSRP CDN $227.95

AS A FRIEND SUGGESTED WOULD I GET THE SAME RESULT BY CUTTING A LARGER OPENING IN THE STOCK BREATHER CASING?
WOULD A DEALER CALIBRATION BE NECESSARY?

ANY OTHER PERFORMANCE ENHANCEMENTS [SPARK PLUGS?]
THAT YOU CAN SUGGEST SHORT OF A STAGE 2 KIT

THANKS FOR YOUR HELP

RIDE SAFE

GENE

Answer
The two best performance items you can install is one, the high flow slip ons (which you did) and the high flow air filter kit. The calabration chip comes with it. That is why it costs so much. Just punching a hole in the breather casing is a bad idea. You dont know how it will flow.
When you do the above you are leaning out the bike. Hench the chip. Spark plugs will not help in the slightest. They all perform about the same.
Good luck and happy riding
Mike