Thank you all! @Nodge68 Remap: tricky as I haven't heard any one in my region who does it. @rob_bell pointed me to Saw tuning in the UK, loved their web site = exciting thoughts!. I could sent them a spare MEMs 1.9 ECU tot week and then fit that but would it work on my cars system? Or would I have to send the actual one on the vehicle leaving me without a car while I wait? I guess their work would address fuel pressure / spray pattern...
I spoke to the guys at the MGF25 show a couple of weeks ago. They haven't remapped a Freelander before! The fuel and ignition maps are all likely to be the same or similar to other MG Rovers of the period, so that isn't the problem. What I don't know is how MEMS1.9 interacts with functions such as the HDC - and on that basis I would send them your ECU, but discuss with them to see what they think is the best way forward.
I am considering getting my 2001 (MEMS3) remapped by them - but this is much easier on MEMS3 as I already have a pscan.eu diagnostic unit that can be used to perform remote remaps on this later ECU
PS from memory, MEMS1.9 and MEMS2J for pre-2001 1.8MPi and VVC respectively, use the same fuel injectors. The bigger difference is between these earlier systems and the later MEM3. The latter use a smaller injector to get finer fuel delivery control to improve emissions for EU3 approval. For you, just use whichever injector you have.
BTW, MEMS1.9 tends to run the engine quite rich. This is to allow for variable fuel quality in multiple markets. On my sprint/hillclimb car, I was able to get another 5bhp and 5 ft.lb torque by leaning out the fuelling and advancing the ignition a little While that is not particularly relevant for your plan, what it does mean is that the system already has a significant margin for upgrades without the engine running dangerously lean. Which means that the car will likely run fine with the planned mods you have. This is true for both my MGFs, which use TF135/ Lotus135 cams, both have 4-2-1 manifolds, both run high-flow air filters and one even has cylinder head porting and both run perfectly and run well within the MoT exhaust emissions required - and have done in this state for 10s of thousands of miles. Happy days