Well it hard to say if it will make a difference; that depends on how long you plan to keep the car. Up to 100k, no not really. 150k, yes.
As far as the switch over, there is no "secret" or "special" way to do it. Pour old oil out, change filter, put synthetics in. Thats it.
You can if you prefer change the synthetic oil every 3k for the first 3-4 times and then go to a 6k shedule, but once again, that does not make that much of a difference at this point and considering you do not have a 2.7 gunk buildup is not an issue.
The only downside to switching to synthetic is the extra cost. Even the very best natural oils break down far faster than the worst synthetic.