Unfortunately, you must rebuild kernel for any modification,but don't worry so much about kernel recompilation as long as you know very well what you are modifying,frankly I don't know that modification you want to do but I can advice you just to be careful in your choices, & it's better to backup your system files (just in case) by the command :
tar cvfp /etc.tar /mnt/d
that backup for /etc because it includes the configuration files for any service on your system.
* The option (p) to keep the path of the optained files &directories.
* /mnt/d is the directory of the compressed file, I assumed you have dual booting (linux & windows) or else you can put the backup on a cd.
* To restore the backup (I hope you don't need it), use the command:
tar xvf /mnt/d/etc.tar
Don't be afraid to recompile,1 of the Linux' advantages is its stability, even if in the worst cases you failed to restore the files, enter the 1st system cd (bootable cd) and make repair by chkdsk.
Good luck & Hope you don't need all that.