I'm assuming you have a post april 2005. if you have, then the glow plugs are likely to be 7v ceramic, in which case I gather that the Etechno will fit right in without any need for a mod or for an ECU reflash - but I'd check with the manufacturer just to be sure. I wouldn't disconnect the MAF sensor - all sorts of difficulties can arise and you will get a check light and code.
As for disconnecting the EGR, some of the lads on ausjeep have tried this - have a look here for the thread:
http://www.ausjeepoffroad.com/forum/sho ... p?t=113434You have to block it off at both ends,and there do seem to be benefits, but I'm not sure of the effect on the MoT gas readings.
As you have the 2005 - have you had the rear LCAs replaced under the recall? If not, get it done. Doesn't cost anything, and makes a difference to the handling.
Has the fuel filter been changed yet? I think its suggested at every other service, but no harm slotting a new one in just to be sure!
Where are you by the way?