3.5 swap?
I'd wait a couple of years and get the new 3.6L 4-Valve motor. I bought my wife a Caravan with the 3.6L motor, it puts out 282 HP and it gets up and moves. Motor Trend has the 0-60 in 7.9 seconds which for a 4500 LB minivan is pretty impressive.
The good news is they are putting the 3.6 in EVERYTHING. Chargers, Challengers, Minivans, and Jeeps, they are probably building over a million a year. In a couple of years they will be cheaper than a hemi in the junk yards.
Regards,
Joe Dokes