[Qmulus]

I have owned an Audi A6 2.7T 6speed for 14 years and an Audi owner for over 25 years, even making a business in automotive electronics. I know the 2.7T very well. Some of what Markus mentions are common issues with them. I have dealt with most of those issues myself and don't consider any of it to be a big deal.

I don't know what he means about manifold and throttle issues. The rest are pretty minor, especially as compared with M96 issues. The Audi 2.7T issues are mostly in the annoying category. Turbo failures are almost exclusively on tuned cars, especially with intake leaks that result in the turbos overspinning. Cam adjuster seals leak (pretty simple fix), but they rarely if ever fail. O2 sensors fail (I replaced two of mine at 110k), but they fail on all cars, especially turbos. The plastic PCV hoses fail, which is annoying, but not serious nor expensive to fix. Later cars with the secondary air injection have problem with combi valves, leading to failed pumps. That repair is probably the worst IMO, but that system can be coded out and the ports plugged. My car is a '00, so it has no secondary air injection. One problem he did not mention was the auxiliary coolant pump, which Audi decided to put in the valley under the intake manifold.

Personally, I don't think I would put a 2.7T in a Boxster for a few reasons. First, the intake plumbing would be a big issue. You will need to find a place for the intercoolers with good airflow. If you look at the front of an Audi with the front bumper off, it is all coolers. Maybe you modify the sides with big scoops to accommodate those. So, you end up with the same issues you would run into trying to put a 996TT Mezger engine in it. The intercoolers are critical to making power on the 2.7T, so that is a BIG issue.

Next, to get more than 300hp, you will need bigger than stock turbos, which means added lag. To me, part of the appeal of the Boxster is the naturally aspirated engine. While it would be fast as hell with a 450hp 2.7T, it would have more lag than a 450hp 3.6 Porsche engine.

Then there is the rest of the fitment issues. The Audi engine is short, but it is also tall and wide. I think the height would be more of an issue than the width, but having not fit one, I can't say for sure.

In my opinion, if I was going with an Audi engine, I would go with a 4.2L V8 from an '01 or '02 S6 or S8. You would have 360hp naturally aspirated horsepower in the most reliable engine Audi ever built. Weight wise I believe it is lighter than the 2.7T as it is all aluminum (the 2.7T is a cast iron block), with no turbos and the additional intake plumbing required. You would still need to deal with the height of the V8, which is the same as the 2.7T. You also have a bit more length, but it is considerably shorter than a Chevy LSx. I like the idea of a Boxster with a Spyder conversion (getting rid of the stock convertible top) would open up a bunch of room on the top of the engine.

Concerning the Audi V8s, I would stay far away from the later V8s with timing chains. These are the M96s of Audi engines. Well, maybe not quite that bad, but close. They are short, but the cam adjustment actuators, chain adjusters and guides fail. Fixing that is ~$3k in parts and 40hrs labor.