Joseph, I'm having problems doing that because of the VirtualBox kernel modules, which don't want to compile for the 4.16 kernel. Here's what I get why I try to re-install dkms and virtualbox-dkms:

$ sudo apt-get install dkms virtualbox-dkms
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-4.13.0-26 linux-headers-4.13.0-26-generic
  linux-image-4.13.0-26-generic linux-image-extra-4.13.0-26-generic
  linux-signed-image-4.13.0-26-generic
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
  dkms virtualbox-dkms
0 upgraded, 2 newly installed, 0 to remove and 11 not upgraded.
Need to get 690 kB of archives.
After this operation, 5,319 kB of additional disk space will be used.
Get:1 http://nessus.rodsbooks.com/ubuntu xenial-updates/main amd64 dkms all 2.2.0.3-2ubuntu11.5 [66.3 kB]
Get:2 http://nessus.rodsbooks.com/ubuntu xenial-updates/multiverse amd64 virtualbox-dkms all 5.0.40-dfsg-0ubuntu1.16.04.2 [624 kB]
Fetched 690 kB in 0s (1,499 kB/s)        
Selecting previously unselected package dkms.
(Reading database ... 550655 files and directories currently installed.)
Preparing to unpack .../dkms_2.2.0.3-2ubuntu11.5_all.deb ...
Unpacking dkms (2.2.0.3-2ubuntu11.5) ...
Selecting previously unselected package virtualbox-dkms.
Preparing to unpack .../virtualbox-dkms_5.0.40-dfsg-0ubuntu1.16.04.2_all.deb ...
Unpacking virtualbox-dkms (5.0.40-dfsg-0ubuntu1.16.04.2) ...
Processing triggers for man-db (2.7.5-1) ...
Setting up dkms (2.2.0.3-2ubuntu11.5) ...
Setting up virtualbox-dkms (5.0.40-dfsg-0ubuntu1.16.04.2) ...
Loading new virtualbox-5.0.40 DKMS files...
First Installation: checking all kernels...
Building only for 4.16.0-041600rc1-generic
Building initial module for 4.16.0-041600rc1-generic
ERROR (dkms apport): kernel package linux-headers-4.16.0-041600rc1-generic is not supported
Error! Bad return status for module build on kernel: 4.16.0-041600rc1-generic (x86_64)
Consult /var/lib/dkms/virtualbox/5.0.40/build/make.log for more information.
Job for virtualbox.service failed because the control process exited with error code. See "systemctl status virtualbox.service" and "journalctl -xe" for details.
invoke-rc.d: initscript virtualbox, action "restart" failed.
● virtualbox.service - LSB: VirtualBox Linux kernel module
   Loaded: loaded (/etc/init.d/virtualbox; bad; vendor preset: enabled)
   Active: failed (Result: exit-code) since Tue 2018-02-13 13:30:45 EST; 3ms ago
     Docs: man:systemd-sysv-generator(8)
  Process: 9835 ExecStart=/etc/init.d/virtualbox start (code=exited, status=1/FAILURE)

Feb 13 13:30:45 louiswu systemd[1]: Starting LSB: VirtualBox Linux kernel m.....
Feb 13 13:30:45 louiswu virtualbox[9835]:  * Loading VirtualBox kernel modul....
Feb 13 13:30:45 louiswu virtualbox[9835]:  * No suitable module for running ...d
Feb 13 13:30:45 louiswu virtualbox[9835]:    ...fail!
Feb 13 13:30:45 louiswu systemd[1]: virtualbox.service: Control process exi...=1
Feb 13 13:30:45 louiswu systemd[1]: Failed to start LSB: VirtualBox Linux k...e.
Feb 13 13:30:45 louiswu systemd[1]: virtualbox.service: Unit entered failed...e.
Feb 13 13:30:45 louiswu systemd[1]: virtualbox.service: Failed with result ...'.
Hint: Some lines were ellipsized, use -l to show in full.

Is there an updated dkms and/or virtualbox-dkms to go along with the 4.16 kernel?