here's a good diagram that shows all the pads and tensioners:
http://www.pelicanparts.com/techarticles/Boxster_Tech/16-ENGINE-Camshaft_Swap_and_Chain_Tensioner/Gp1800.pdf
various levels of work to replace the various components; tensioners can be done with engine in the car, variocam pads can be done by pulling cam covers, ims pads require complete disassembly. the actual replacement items are not that expensive (lne make a billet replacement for one of them); all the cost is in the labour, and I would suggest to really vet your shop before you let them too far into your engine.
the variocam pads have been updated by porshe to a harder material, are not *that* much work to get at (well, I was quoted 12 hours) and are probably the cause of your deviation bumping into the +/-6 limits.
tough call.
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