Using i2c protocol with xbee

Hello.

Currently i'm working on a project with 2 Arduino Nanos and 1 Arduino Mega. I use i2c protocol to exchange data(integers) between Nanos( i use them as a slaves) and the Mega(master). I want to upgrade my project with xbee modules and before buying them i have couple of questions to ask.
This is the model that i want to use : XBee 1mW Wire Antenna - Series 1 (802.15.4) - WRL-08665 - SparkFun Electronics with this kind of adapter : https://fluxworkshop.com/products/biaa100012-xbee-usb-adapter-module-keyes-blue.

My questions are :

  1. Do i need to make big changes to the current code in which i have implemented i2c protocol?
  2. How great will be the delay between sending and receiving the data?

Do i need to make big changes to the current code in which i have implemented i2c protocol?

Yes. The XBees are, effectively, serial devices, not I2C.

  1. How great will be the delay between sending and receiving the data?

That depends, to a great extent, on how you configure the XBees. If you put one in broadcast mode, and the other in listen-to-everybody mode, the delay can be significant.

If you put one in listen-to-Bob mode, and the other one in hey-I'm-Bob mode, then the delay will be nearly non-existent.