This was the one.
Alois the genius
A lot of work, but worth it.
extract
"The conversion work to accept the 911 engine is fairly comprehensive. Even though the Boxster and 911 share the same basic floorpan and front suspension, everything aft of the seats is totally different. The 911 engine sits behind the rear wheels with the gearbox ahead of it while the Boxster is a mid-engined car with a rear-mounted transaxle. Thus, the gearbox used is the Boxster S six-speed unit or the five-speed Tiptronic"
"The 996 motor is slightly taller than the Boxster’s, but it weighs about the same – perhaps a couple of pounds more. To make the engine fit in the Boxster, RUF fabricates special engine mounts that allow the motor to sit a bit lower in the rear subframe. In effect, the motor is dropped down to retain the same overall center-of-gravity as with the Boxster engine. The anti-vibration parts of these new mounts are stock Porsche. Extra cooling for the engine comes in the form of the 911 GT3’s center radiator, which neatly fills the space behind the 911 GT3 front bumper/spoiler.
"