Hi Danilo,
I was very lucky as the Lepai that I bought for £18.99 a few years back has a genuine TA2020 in it. You can still buy the chip from a European distributor for about £9.00, well until stocks run out!
Really enjoyed modding the little amp and have spent £12.00 to date on it so not bad. The sound quality has really amazed me and it still works well. Not sure what else to try now as I've run out of ideas but have removed the resistors at R42 and R43 since.
Hope that it lasts as I really like the smooth detailed sound it produces - the pre-amp bypass mod giving the biggest effect and I found the others quite small by comparison.
Regards
Chris