I have no firsthand knowledge on the Cardas Teflon cap upgrade. I have only read good things about the Cardas caps coupled with the fact that Cary uses them in their new Founders edition 211. My experience is limited to V-caps and Mundorf in an 805 amp. The V-caps change the 805s character but does add another level of transparency and speed. The Mundorfs take away a bit of the 805s warmth, adds a touch of quickness, more bottom end extension, and a bit more transparency.
Because Cary utilizes point to point wiring, any competent tech can perform the cap upgrade without breaking the bank.
With respect to tubes and the Rocket 88, the combination is almost endless. What I generally suggest to anyone who purchases a new tube amp is to live with the amp for an extended period and note the amps short comings i.e. lack of bass or extended highs etc. This will give people who have rolled tubes in a Rocket 88 a basis to make a recommendation.
Because Cary utilizes point to point wiring, any competent tech can perform the cap upgrade without breaking the bank.
With respect to tubes and the Rocket 88, the combination is almost endless. What I generally suggest to anyone who purchases a new tube amp is to live with the amp for an extended period and note the amps short comings i.e. lack of bass or extended highs etc. This will give people who have rolled tubes in a Rocket 88 a basis to make a recommendation.