Just check the coils first, make sure there isnt any burn makings or white lines (similar to cartoon lightening strikes, as an example :S lol)
different ecu can be anything from a second hand PFC, Link, Microtech ect ect, all down to you and what you like/want and who you decide to go with with tuners.
Yes mines are tuned in Japan, so different fuel, your friend had his on the dyno to check that it was fine? has he got exactly the same mods on his car as you?
Can pick up a set of aftermarket coils for about $500 give or take. theres probably alot of maintence items that you can fix up to make the car alot better/smoother to drive.
I havnt had much experience on the coast here with tuners, i get mine done in brisbane, i might be able to ask if the workshop can do me a favour and run your car up on the dyno then you throw your friends ecu in and run it up again, see what its doing?
HOWEVER, i would strongly recommend fixing coils before throwing it on the dyno lol.