I have heard that too that some tuners aren't able to set greys up right so was another reason
Main one apart from fuel supply was the fact they are a more modern unit and I presume will give a better spray and ergo less chance of cocking up and buggering my engine

Power wise was thinking around the 340bhp mark don't want to go chasing numbers just want a tracktable road car that's fun when I want it
Sure 450bhp would be nice to quote in the pub but I wanna drive the thing..!!

Just out of interest what are the power ranges that are reccomended for the seimens