I have the FR+ 150 TDI. My mate has the cupra.

The difference between the two are:

FR+ has cruise control, reversing sensors, center arm rest for driver,

Ermmm, Nope to all those (as standard anyway).
The engines and suspension setup is the same.
The Cupra Used to come with a Cd changer but i don't think that lasted for long. The FR's don't as standard.
 
I have an FR and a mate of mine has a cupra. We parked them together a couple of weeks ago and the only diff we could spot were:

Wheels (both 17's but diff - mine are better!!!), Head unit/changer, seat trim (but i guess that could just be differently speced from new), and i have sliver bits to move the air vents!!!

From what i can make out, the FR replaced the cupra, but is basically same car - as others have said i think.