Thank you for your interest in Eurocomponents’ wide tire swingarm for Twin Cam Softails.

No, the wheel base does not change, it is the same as stock.
The kit is completely bolt-on.
The only things which are not included are the rear wheel and pulley: you can choose from the different designs listed on the website at the following link:

https://www.custom-motorcycle-parts.com/eurocomponents-custom-motorcycles-news/300-tire-330-tire-single-sided-swingarm-conversion-kits-for-twin-cam-softails/

Please let us know if we can be of further help.
Thank you and have a good day.

Lorenzo
…………………………………………………………
Eurocomponents, Inc.
Daytona Beach, FL – USA
Phone 386-868-0696
https://www.custom-motorcycle-parts.com
https://www.facebook.com/CustomMotorcycleParts
https://twitter.com/ChopperParts