Hi saltire,
I can only reply re the MK6 GTi aspect:
If not read so far, you would be well advised to read the below forum thread (you should also listen to the uploaded sound byte link by Rocket Ross on that thread demonstrating 'the timing chain rattle' on a MK6 GTi so you know what to listen for and you should carefully read people's experiences around the issue:
www.golfgtiforum.co.uk/index.php?topic=262793.0Having recently bought a MK6 GTi from a main dealer, I went through a very thorough research process pre sale.
I found out what preventative work could be done to minimise the likelihood of the dreaded timing chain tensioner failure which will inevitably result in very expensive catastrophic engine damage. I put the preventative work needed to the selling dealership in writing pre sale and at one stage before completion, even offered to pay for the parts if they would cover the labour and undertake this work before I bought the car. They declined on all requests.
I also contacted Das Welt before buying the car and they assured me that the car would be covered in the event of tensioner failure and/ or consequential damage from a failure.
The selling garage reassured me that robust checks had been done and the tensioner/ chain would be fine.
I was never convinced and was sure I could hear an abnormal noise on start up, particularly from cold starts.
The car is currently having what I consider to be major after sales remedial works done, including replacement of the timing chain tensioner and associated parts.
Others will tell you to relax, enjoy the MK6 and don't worry about something - e.g timing chain tensioner failure - that might never happen. I don't agree. If you can reasonably foresee a major defect arising, then why for the sake of a few hours work and a few hundred pounds would you take such a risk on such a large 'investment' that could leave you quickly and hugely inconvenienced, amongst other things.
My pre sales research and record keeping 'saved me' (for want of a better term) on this and other serious issues that have quickly manifested with this car, resolution for which is ongoing.
My understanding is that the list of parts required to safeguard any future timing chain tensioner failure takes approximately 4 hours labour in order to remove the old and refit the new, the parts list being as follows:
Part No & Description
06K109467K - upper tensioner x 1
D 174003A2 - sealant x 1
N 10552402 - hex bolt x 1
N 10701501 - bolt x1
N 90596906 - bolt x 1
N 91029602 - bolt x 1
WHT001760 - damper bolt x 2
06H109210Q - timing chain cover x 1
N91096702 - bolts for cover plate x 10
Hope this helps and assists you in some way.
Personally, if there was no record of the timing chain tensioner having been upgraded and replaced, I wouldn't buy the car from a main dealer - with all the technical know how and resource they should have on tap - unless that replacement was part of the deal.