For years I've had success using RAM mounts for gear I use in my chase vehicles. I used a RAM-246U VESA mount for a widescreen monitor in my Honda Civic during the 2008 season. In 2011 I looked for a laptop mount for my 2003 Subaru Impreza but RAM only had a no-drill base for model years 2006 and newer. I had RAM send me the CAD drawings and I determined that the RAM-VB-169 base would work in my 2003 after widening the seat bolt slot a little.

When I got my Subaru Crosstrek I had to search again for a suitable base for the laptop mount. I wanted to continue using my seat bolts for mounting so I wouldn't have to drill holes through the floor. But RAM doesn't make a no-drill base for the Crosstrek. So I set out to modify my existing base. The VB-169 base was about an inch too wide for the seat bolts so I had to expand the seat bolt slot all the way to the edge and grind away some of the angle reinforcement:

Right seat bolt

I also had to stack some washers under the base mounting tab because the seat bolts are flush mount on the Crosstrek. The image below shows the other side close to the laptop mounting pole. This provides the brunt of the support for the laptop and I didn't have to grind anything away. I only had to add another stack of washers under the mounting tab:

Left seat bolt

I've run with this set up for the entire season and it's been solid so far. If you choose to mount gear to your seat bolts, be sure to re-torque them to specification and recheck periodically.