I did this on my Gt sensor, the only thing I came across is the frt derailleur adj, since your bike is now sitting higher in the middle your chain will want to drag across the bottom of the derailleur cagein certain gears, how ever when your seated on the bike your sag will usaualy put it with clearance, for me the extra clearance I get from a higher center is worth it, with the idrive on the sensor my bottom bracket is low so the extra clearance is helpful. It does shorten your wheel base and takes a little getting use to but it rides nice just a little more twitchy
You could probably get away with and just run enough sag to match the stock spec. Keep in mind that running too much sag will probably result in bottoming out, so you might have to run volume reducers to correct it.
Running at recommended sag with a shock with a longer eye-to-eye will cause your bike to sit "high" and will result in a higher bottom bracket, steeper head angle and seat tube angle.