Buy the OEM and move-forward! I was a retailer of WeatherTech for 10 years and they are a great product however, they are not custom fit and don't have the fixing points like oem. Plus, the rear are not attached like the oem. This is one area where I would just buy oem and motor on happy with your purchase; all be it a bit more expensive. All my Rovers run oem floor mats (even though I can get aftermarkets i.e WeatherTech, Husky, Catch-All for next to nothing).
Ian
Ian