If its running perfect then why do you need to touch it? If it ain't broke don't fix it right??

A well tuned MFI system is fine if maintained properly. Many people are putting their cars back to MFI to keep it original, asking and fetching crazy money in this day and age. To an extent there is some truth in plug and play with the OFAB/C ecus, however, if you are going to be spending money on this sort of thing it would be better to start off with a new wiring loom as electrical issues haunt rs turbos, finding an xr3i/frst loom that's in good nick will also be a challenge. They do tend to pop up now and again such as the link I just found on eBay. You can buy off the shelf ready made wiring looms but they don't necessarily fit perfectly in the bay as they are just a generic size in length. Think about what standalone management you want to go for. OFAB/C is old hat and with the technology that is out there nowadays you can get something a lot better due to being more precise with fueling and other ecu features that OFAB/C just can't do. Another decision you will need to make is who will be mapping the car. Alternatively, you could have a chip in OFAB/OFAC ecu and just run beige injectors at around 200 BHP but there are a lot better injectors that flow better and potentially give you more horsepower should you want it. You have the right turbo and bottom end for good power. OFAB/C isn't all that once you realise the power of standalone management and how it can transform an engine.

The easiest option for me might not be the easiest option for you. I wanted to learn how the whole conversion works, the easiest thing for me would have been to just send it to someone who knows what they are doing to do it for me. There are several tuners who can do the conversion for you to save you all the agro of having to find parts etc but brings one back to the whole time vs money debate.

Ultimately its your decision, good luck with whichever you decide to go for.