MBL 1611 E DAC

Hello, I have the above DAC which I use in combination with the 1621 A Transport with tremendous results!! However I am now teased by the fact there is an upgrade available to F status, which I understand, converts SACD signals as well. As I have no imminent desire to play SACDs I am wondering whether it would be worthwhile upgrading (£1,500.00) solely for Red Book playback, a significant improvement would be a great achievement indeed and, albeit, as big a welcome surprise. Any comments would be greatly appreciated.

many thanks

John