My girlfriend just got her license a few weeks ago. While taking the course at our local Harley dealer, she fell in love with the 2015 883 Superlow. She likes the low seat, the long bars, and the wide tank. That's all well and good, but that bike is out of her current budget. I found her a 2010 883 superlow that fits her budget, but it has the taller narrow tank she doesnt like. This is the long way of asking if the two tanks are a direct swap for each other, or finding out what would be involved. This would be her first motorcycle so i'm not overly inclined to get a brand new bike right off the bat.

 

I would ask the dealer to be sure. I think the fuel petcocks Will be a direct swap but not sure. Also the seat she currently has needs to be taken into consideration too. Getting a larger tank will affect this.

 

Look at the price tag, too. Not sure, but that tank and seat from dealer will probably be north of $1,000.

 

with a very little work you can put any size FI tank on any model sportster. You may have to shorten or lengthen the overflow hose and make a seat bracket for the front to compensate for a longer tank a shorter tank's no problem if you don't mind a gap in front of the seat & tank.
I put a 4.5 gal 1200 custom model tank on my 72 replacing the 2.1 gal tank ( from Ebay ). It was easy to do. One front & rear bolt, swap the FI pump from stock tank, shortened the overflow hose. Since I was changing seats I bought one for a 1200 custom instead of the 72 and it slipped right in ( also from Ebay ) total cost of about $500= for tank & seat.
P.S. I painted the tank myself so no cost except materials add about $1K for a paint job by a pro or dealer