Just a newb opinion,
I went ahead and installed vector light's 6.0 lilo to the VL partition itself so it'd leave my other bootloader alone. If you already have a bootloader managing boot on that comp. Depending on which one, it should either pick up on the new distro installed. Or it can be added manually, in the case of grub legacy ( which I use ) in it's /boot/grub/menu.lst
With grub2, sudo update-grub in terminal should pick up on and add the new VL install to the boot menu and/or running update-grub as root user whichever syntax the distro controlling the bootloader uses. Have no experience with lilo. Would assume if you install it to sda/mbr ... etc. Then it wouldn't have any problems managing all the installed OS's on your box. With or w/o some tinkering being necessary. I just prefer grub legacy ... Found it easy to boot distro's editing the menu.lst, even for one's I skipped installing whatever bootloader comes native with em altogether.