Not sure where to begin....I will try and address some of the questions and concerns from reading the previous posts on this thread. From start to finish it took me 3 years. There was definitely a lot of time that I didn't work on it, sometimes months at a time and many times. My engine is the F20c. Mechanically it was pretty straight forward, I did have the oil pan notched to clear the cross member and steering rack so the engine would sit low to close the hood and for alignment of transmission and driveshaft etc. From the start I knew I needed to smog it in. Ca. So I am using the stock Honda ECM and wiring and all the Honda s2k emission components/modules. A big mystery was how to manage the fuel tank pressure for emission purposes so it wouldn't throw a ck engine code, luckily BMW must have known they would need to do this in the near future as the e30 had all the vacuum lines and fitting to easily tap into. This may not sound like a big deal but to me and trying to smog it and be legal in ca this was huge. Motor mounts and trans mounts were easy and straight forward, I used the Honda radiator, had a hydraulic line made for the clutch with a BMW fitting on one end and Honda on the other, done. Easy to bring fuel to the motor too. Absolutely no mods to the bmw throttle cable to connect to the S2k motor.Plenty of room and clearance exhaust wise. I struggled with the drive shaft for a bit after it was on the road. At first I just put the front slip joint of the Honda shaft onto the otherwise complete BMW 2 piece shaft, that also has the slip joint in the middle, so I had 2 slip joints and a 2 piece shaft. Kept having vibration and clearance problems, I finally found that a one piece shaft with tha Honda slip joint in front and of all things I used a Toyota Tacoma joint at the rear to bolt to the BMW rear flange, same exact pattern. Now it is robust and smooth at all speeds and loads. Obviously using the s2k 6 speed trans which is an absolute gem of a transmission. I also am using the digital instrument cluster and push button start from the s2k. With out a doubt the most difficult part for me was the wiring. I am no expert at any of this especially wiring. This is why it took so long to complete. The 2 different era's of cars, 2 different mfg'ers, 2 different origins. I wanted it to be clean and finished in a way that everything appears stock and clean and reliable. Not sure how much lighter the Honda engine and trans are, I'm guessing between 100-150lbs. I have been driving it for over a year as a daily driver and put over 20k on the swap (knock on wood), all trouble free other than sorting out the driveshaft. All and all the car drives and performs amazing, everything I hoped it would be. It drives like a kitten when you want it go be and when you put your foot in it, it comes alive like no car I've ever had. This is my first BMW and I fell in love with it and just wanted more power and one thing led to another. I avg 25-27 mpg the same as with the m42, I have gotten over 30 mpg on longer trips. I don't know exactly what my car weighs but I know it is several hundred pounds lighter than a s2k. I am thinking it may have a 1-10 lb/hp. I'm sure there is a lot I left out. Bottom line, I love the e30 handling, practicality and looks. Seats 5 if needed and is a sleeper. But it was a lot of work. Feel free to ask any questions. I can try and post some pics later. For now you can search on you tube "318is s2000" it is a totally funny video because it is literally the first time I drive the car and the emotions were pretty high. Thanks
