Could be a very pricey driveline.  Remember, most Porsche motors have those
crappy Mahle pistons that run directly in aluminum bores, similar to a Vega
motor.  Finding a competent shop to handle any kind of
block/piston/ring/head issues is difficult, the Mahles are also difficult to
find and  to pay for.  But if you have the spendable income, there's tons of
knowledge and available technology to make a strong and relatively
dependable Porsche motor. It's an accepted fact that the more power you
wring from a motor, the shorter it's lifespan will likely be.... I think the
GT2 996 water pumpers are making normally aspirated 475 rwhp and the turbos
are around 600hp..The turbos were unbeatable, if they lasted a whole race
and their drivers kept em on the track...
  I'd guess, from my PCA racing days, that you could easily find 993 motors
(water cooled heads only)  'cheap', because for a while, those were the
motor of choice for rich-guy racers, then they all started buying factory
made 996 Cup Cars...at a couple a hundred grand, each..
  A Porsche motor into an Air Cooled van would be pretty neat.   The newer
Porsche Factory Cup Cars, they call for a motor rebuild at 100
engine-hours...so probably a bit too "highly strung" for use in a
Campmobile..You would probably have issues with legality also, since these
cars have no VIN as 'race-only' machines..
  Don Hanson