I'm sorry to hear of your ink dripping problem after replacing the dampers!
Did you replace the whole ink system (cartridge chambers, lines and damper assembly- all as one unit), or the individual dampers themselves?
Was there resistance when you flushed the print head with PiezoFlush?
Did you flush all channels in the print head, or just the magenta channel you were having trouble with?
Did you clean the bottom of the head after flushing? If so, did the paper towel come out whole after cleaning (and there's not a piece stuck to the bottom of the head)?
This dripping could be caused by a few things, including a bad connection, damaged print head, defective or damaged damper, etc...
It's hard to say if this is fixable (not knowing the cause), or if it's batter/easier to buy a new printer.
The R3000 is mechanically very similar to the 3800/3880, though the R3000 uses totally different carts.