I'm all for tuning, and I agree that there is an almost fuddy duddy spirit in here, which is quite disenheartening TBH. On the other hand we have some parts of the membership such as myself who throw all the toys at it, including a hybrid turbo. (I rebuilt my GT1749v as a GT1752v) We've also
@Diesel Do who has a company, "MuddyMods" making mods for the hippo, including sports exhausts, induciton kits, improved intake ducting etc.
However I'd counsel you to tread lightly with the tuning on the freelander, as I've been informed that the freelander has some inherent design limitations. One such limitation is the "TD4" M47R (R for Rover variant) has a weaker crank than BMW's regular M47 engines. Also, it appears that the Jatco JF506E autobox is pretty close to it's torque design rating / limit on TD4 in standard tune. I've seen one dude on here with a snapped crank, and know of someone else who had auto box problems and reckons their autobox was torched by a tuning box turned all the way up. But that being said, you've got to ask yourself, what age and condition was the box in before the tuning box and this failure?
There appears to be some misunderstanding on the benefits of a larger intercooler, as well as allowing better cooling supporting higher boost pressures by means of dissipating the associated increase in charge temperatures, the lager volume is less restrictive and as such allows the intercooler to flow better, increasing the width of the torqueband, improving throttle response, etc. These improvements will also benefit from the fact that the original intercooler will by now be ~15-20 years old and internally clegged up with oil gunge as well as coated externally with a nice layer of insulating corrosion.
IMHO the freelander seems to have a decent enough map at the bottom end, but it looks to me as if it's been mapped to fall off a cliff at the top end, and I'd reckon a good map would enhance it nicely. I've not yet mapped mine as like every tuning project you need to get the fundamentals right, and mine is lame, lots of smoke minimal poke, but not a boost leak. I suspect I've not got a good seal on the injectors from some previous trauma/work, but our hippo is the third car in our household and as such a back burner project, so I'm not in a hurry to investigate it. However, I will get around to it and slap an intercooler, muddymods turbo ducting and a map on it.