Engine swaps are not easy. Even replacing a stock rebuild is complicated by the interconnected nature of modern cars. So what happens when you outgrow the power limits of your block? Most enthusiasts choose to sell their cars for something faster, and to be honest that is why duPont REGISTRY exists. But for those who have formed an emotional bond to their automobile, a larger engine is the only way to go. Many BMW purists were shocked when the E92 series M3 was introduced with a 4.0 liter V8. Another point of confusion was the limited sales of the 1M in the US. Not to be confused with the legendary M1, the 1M coupe was a compact & nimble machine powered by a twin turbocharged straight six. dismantled his 135i and endowed it with the drivetrain from an E92 M3. Leaving the V8 in stock form would have been completely acceptable, but Dinan's 4.6-liter stroker kit was too hard to resist. So as long as you are building a new engine, go ahead and integrate the A/C, stability system and traction control? Add a roll cage and carbon fiber wheels and you have a supercar. We don't want to see the final bill for the time and parts involved, but we enjoy tiny cars with giant power. Tell us your favorite engine swap in the comments below, and LS owners please respect your German friends. Stay with us for more clips from Jay Leno's Garage.