Hopefully some points regarding use of my car will offer insight
I`ve done near 40000 miles now since the IHI was fitted in Dec 2005 - i`m still on the original exhaust manifold/turbo exhaust housing/and Jabba downpipe - no obvious signs yet of heat stress/cracking/warping etc.
I`ve done 20,000 miles since June last year, when I had a new compressor and cartritdge fitted - the original set having failed as a consequence of a faulty DV- with no major problems.
The car has done in total, 80000 miles now, and is running as well as ever - oil consumption is negligible - and the original, standard VAG components have stood up very well - pistons,rings,gearbox,diff,drive shafts,wheel bearings,all which were areas of concern to me as a consequence of the increased power, have shown no sign of premature failure.
I am still, 40000 miles on, using the original Sachs clutch fitted by Jabba when they did the IHI conversion.
I have not `spared` the car in any way - all the mileage has been on the public road but no doubt I do drive `enthusaistically, whilst having mind of my own safety and that of other road users.
The setup was mapped originally at 1.6bar but with the miles passing, makes more boost if allowed to - as you can see from the videos, it will make 1.7bar+ at the top end.
In the midrange it will make 1.8+ bar peaks, easily - I see that on a daily basis -mostly as a consequence of the Aquamist - often in circumstances of say, waiting to overtake on a trailing throttle - the temp of the intercooler drops right down - once the overtake is commenced, and the throttle floored, the Aquamist kicks in[1 bar] and there is a definite cooling effect of water/methanol mix on the temp of the inlet charge - there is a lot of torque produced, much more than when the car was originally on the dyno, and this may well test the limits of the standard rods - that`s why if you`re going to run a setup like mine it`s I think it`s worthwhile changing the rods.
Also the stronger rods do offer some protection against mishap - such as the failure of boost control the happened to me the other day as a consequence of the leaking N75 pipe
I do keep a weather eye on things via the spa boost/egt gauge - an essential bit of kit for me - and I constantly monitor and trim the available boost if necessary using the boost controller.
Regarding EGT and IAT - the highest EGT i`ve seen is 895 degC downstream of turbo and that was after running at full bore [170mph+] for a couple of miles.
Last summer I spent some time with Vag Com logging the IAT and mostly they were glued to ambient - it took a good thrashing and warm weather to get them to nudge past the 30degC marker so the Aquamist does
help. You can actually see in the log, a drop in the IAT when the Aquamist cuts in.
Despite fears about using water/methanol injection over an extended period to date after 40000 miles use there have been no apparent adverse effects as far as reliability of the internals goes.
In my book, the running costs are amazingly low for the Porsche+level of performance available - i`ve relpaced timing belt/water pump/ plugs/lambdas/MAF/N75, all as a matter of routine preventative maintenance.
I change the oil and filter [Mobil 1] every 5000miles - always warm it up, before I use the performance, and cool it down afterwards - and really that`s it!
I am going to keep the car, so without doubt I will eventually have some form of failure. I really don`t expect hardware to last `forever` especially when run at such high specific outputs.
I will probably look anyway to renewing the turbo in 20,000 miles if not before, as preventative maintenance.
I`ll keep you posted!