The 340A with a RAM Conversion is a pretty sweet ride, and alittle faster (5-7 kts) than a 414 with the same RAM Conversion.
335 HP engines, VG Kit (increase MAX weight), etc.
You're looking at 200-210kts (depending on altitude), 40 gals/hr at cruise, and depending what fuel tank config you have, a 3-4 hr plane with an hour reserve.
If you're planning on carrying more than just your fam (wife/2 kids) in the plane, it might be better to look a 414 (tip tank model). You get roughly same performance with a larger (wider) cabin.
$400/hr is a good ballpark number.
What's your price range?