KT-88/ 90 choices to replace my new stock tubes

I am trying to decide on one of these tube types for a new pais of quicksilver V4 amps I just bought. The stock tubes sound good, but I feel they can be improved upon. My frontrunner is the JJ tesla KT 88 ( around $75 a pair) , having had good results with this tube previously with another amp. I am also considering the EI KT-90 , which I heard was quite good with the exception of the newest ones( mark 3 perhaps). I am open minded and the JJ tesla price range is fine, but I dont want to spend too much over their asking price.Thanks in advance.