World's 1st B8.5 Audi A4 with 2018 A4 2.0T B9 engine & S4 DSG DL501 B8 transmission ! 

I'm going to answer this in the following order of your questions It was all an easy direct bolt on using all OEM parts for both engine & transmission. 2nd Incorrect the B9 ECU will NOT work since B9 Audi's uses a Flexray LinBus network to talk to the CANBUS modules. Unlike the B8/B8.5 they only use CANBUS therefore your B8 modules are completely coded & registered differently in a B9 meaning that your B8 radio, airbags, AC, lights etc will not communicate with the ECU which will cause network issues in the car Hence you will need to import from Europe the Gen 3 A4 ECU from a B8.5, the engine mounts and the complete wiring harness for that car. What is good about the B9 Audi's is that Audi separated the engine harness in 2 separate looms of cable, what I mean by that is that whatever controls 98% of the B9 engine, it's harness is located on the engine itself meaning the left side of ECU. All you would need is to remove the ride side connector of the Euro A4 engine harness & manually repin what your car will actually need. It's a lot more complicated to explain but all my videos from earlier this year to now explain all of that in detail. The engine swap was very easy & if I had a manual transmission, I would have had this car running back in 2019 with this engine. Since if I were to use my CVT transmission to at least get the engine started running & driving it would require me to manually pin the transmission & recode the transmission 3 times. What I mean by that is that I wanted to go with a B9 DSG which didn't work, oh well my 3rd option which was my original option do to since 2015 was put the S4 DSG transmission. So to summarize your question, everything was very easy with the engine, my biggest issue that I knew would give me headaches would have always been getting the transmission to work. And that if you were to sucessfully get this done in one gulp then it could cost you about $5k in parts & another $5k in labor. In my case money is not a problem & I plan to keep this car for life, as long as it's built reliably then I don't have a budget.

If you are referring to gearbox shaking then your best bet to check to see if your engine & transmission mounts to see if they are worn out.

@@MotorHeadTech I forgot to mention, the gearbox was changed under warranty to 80,000 km. but the new gearbox after 12,000 km. it started to jerk and vibrate like the old one and Audi says it's normal😁 it doesn't seem normal to me plus when I put it in Drive or P or when I almost stop at the traffic light there are some clicks in the box🤔

It's normal for gearbox to jerk to a cetain extent, if it seems worse than normal like I said either engine & transmission mounts or maybe even it needs a software update. But I doubt the mechatronics is the issue, nor the transmission itself since you had it replaced.

Well technically you can run an all wheel drive quattro transmission like the multitronic zf6 or zf8 found in the a4 quattro, q5 and s6 for example. You'll just need the correct transmission modules, wiring harness (do some custom coding/reprograming and custom wiring/mating). You might also need the quattro a4 transmission & dogbone mount. Nothing is impossible, it just requires alot of skill, time & money. And only by then you'll see the output shaft of your 'upgraded' transmission move freely, since you won't have a driveshaft nor differential to drive quattro, unless you want to do a quattro conversion. Because it doesn't make sense to run the car on a fwd setup at that point. Easiest swap would be a 6 speed manual swap, simple & less expensive, the humble mechanic on youtube did a manual swap to his s4 b8. In my opinion, it's easier to sell the car and get something suited for your needs, unless you want to be like me and have & work on a project for years.

I have the cold side (front side) of my turbo for sale

@@MotorHeadTech dang.. I need the hot side. you think its worth it to buy a used one from ebay? Lol

Ebay is fine as long as you check part # & fitment & seller reviews