there youtube video that show this dude, swaping the nosebridge piece converting regular radar to XL , It alway easy to take off the nosebridge but it a pain to put back on.
I have the radar and radar xl. The radar range is the largest lens in the radar. Except the XL . They are not interchangeable. Djhype66 is right, YouTube has a lot videos on the subject. Good luck.
To fit an XL lens onto your standard Radar frame you would need to swap the nose bridge piece from the XL to your standard frame, otherwise they aren't compatible.