Tube upgrade options for Dodge 8 preamplifier?

We recently purchased a Dodge 8 tube preamplifier:
http://www.doge-audio.com/products/doge%208.htm

The Dodge 8 comes with (4) 12AT7 and (4) 12AX7 Chinese tubes. I've read Chinese tube are not great sounding because they tend to be too bright.
Any thoughts on this?

Also, the recommended tubes for the Dodge 8, according to reviewers, are NOS RCA 12AT7's and 12AX7's; much warmer sound.
Would you agree or disagree?

All suggestions are accepted and appreciated.

Thanks!