Hi Wyan,
I have the first WA5 on the market, bought it back in June, 2007....fantastic headphone amp, AND speaker amp. Using it with the AKG K1000. Have a new pair of 2 way speakers that sound incredible with the WA5. Grand Teton SE, with 94db sensitivity and 40-27,000 frq response. www.wavetouchaudio.com If anyone is looking for reasonable priced speakers with such natural, effortless etc etc etc sound, that are worth far more than their cost, these speakers have it. With the WA5, it's pure magic.
I have had zero performance issues in 8 years with the WA5! In fact, all the stock tubes still work!
I have tried the stock Shugang 300b, EH 300b, JJ Tesla 300b, and now the Elrog 300b....while those others are ok. the Elrog is so far above them as far as clarity, detail, and soundstage are concerned...no question the Elrog is fantastic. As we all know, tube rolling changes the sound quite a bit, so I would prob go for the upgraded parts first, as was mentioned....one can always tube roll.