Mcintosh C2600 preamp tube upgrade


I recently added the new McIntosh C2600 tube preamp to my system. It's paired up with the MC452 power amp along with Sonus Faber Elipsa speakers and Transparent interconnects/speaker cable.
I"m looking for some guidance with regard to upgrading the tubes in the C2600. Should I, or shouldn't I ? 
Also, what brand should I look for and where should I buy them. And finally, is this a diy upgrade or should I have it done at a audio shop? 
I appreciate any guidance all you audiophiles can offer
ad48170
I auditioned both prior to purchasing the c2600 and to my ears the c2600 paired with the mc452 is a perfect marriage. IMHO tubes and classical music go hand in hand yet when I listen to jazz the 452 has the punch jazz begs for. As I recall the most significant difference between the c2600 and the c52 was the mid range. 
My speakers are Sonus Faber Amati Futura's, but I would assume my conclusion would probably be the same with any good high end speakers.
I recently replaced the stock Mac tubes with Telefunken in the C2500.  Huge improvement  --  should have done it two years ago.  
Glad different tunes worked for you whitecap. Which version of Telefunken are you using?
ad48170

I have the same exact set up as you with MC452,C2600, mcd550 and SF Elipsa. Though I noticed you switched  your speakers to Amati Futura. May I ask what prompted this change. What cables are you using? I love my current set up, but still using cheap blue jeans cables and stock power cords. 
I upgraded the stock tubes which were delivered with my McIntosh C2500 with a matched set of Genalex Gold Lions and immediately noticed more "musical" sounds, especially for voices and natural instruments (piano, classical guitar, violins, etc.)