manasmadaan There are a lot of threads on this subject... Please use the search function...
Tuning Box - MI vs Rail Pressure
Guide to Tuning Boxes and Remaps
Modifying a Diesel for Performance.
Spider or petes...
Ford Figo TDCi Modifications
TMC Motorsport Digital Plug In Tuning Kits
From what I can see on the website looks like they have a rail pressure unit. I dont think IM boxes exist for the 1.3 MJD engine - if they do then they are definitely better then the rail pressure ones.
Ripper ran both a box and a few remaps on his 1.3MJD (Swift)- you may want to check with him.