Turbo
There is a mod for installation of a Subaru WRX turbo for the IO-520 that can be purchased on-line...think it is about $50 or so. It is a simple bolt on in the field by the pilot man. Could solve all your problems with hot and high - as I hear those Columbia helicopter guys can get a bit heavy handed when doing the long lining with the C209. Bloody chopper pilots - don't know a good machine when they pick it up!! I hear that the Vertol 109 doesn't have the guts for plane extractions either!!!
With regards to the problem turning around at the one way trips - I used to take about 100kg of marbles in the front hatch with me and when I would pull up - just through them all on the ground and push the plane around on the marbles. Tried it with bubble gum balls one day - but it was a hopeless failure and got me into a gooey mess with the Chiefs daughter.......
If it is still too tight - old man Wilde used to have a PMA for the "C209 crevice cracker" - the mod where it is split in the middle and rejoined by suitcase clips. So you pull up - split the sucker in half and turn the 2 halves around and clip back together - Just like one of those David Copperfield cut the pretty lady in the suitcase in half trick. Gets a bit flexy in turbulence but it gives the rear seats a great smooth ride.