It replaces k-jet. I didnt either, hence it's taken about 4 months lol, looking back on it, I rekon I could do the whole install in a weekend! It would give you more power as you say your running lean top end, but yer it isnt something to rush into. But if your taking your engine apart and that then I rekon you'd be able to do it.
Just ask that tshirt bloke bout it as he's got a 16vturbo on ms. If you was too get it mapped on a dyno in the end, I rekon I'd budget for around £700, or if you was to get a base map and do it yourself, it'd end being better than what you have anyway, and be bout £200 less.