Well I won't get into the "boosted FS-DE vs. KL" debate. Personally, I have nothing but good things to say about my FS-DE. It dynoed 115whp on a Mustang dyno with bolt-ons, didn't burn oil and I never had a problem with it for the 3 years I was running it, and it had 132k miles on before it went into it's new home in Josh's P5. Though I understand other members motors burn oil and have a short life.
I swapped the motor simply because I love my P5 chassis and have a lot of money into it and my FS was getting up there in mileage so instead of buying a new car, I simply wanted to swap in the KL because I'm an N/A kind of cat. Boosting an FS-DE seems like it causes reliability issues with a lot of members. And honestly, I don't know jack s*** about turbo's or superchargers. I wanted something reliable with a little more power that I could bolt in so I bought a KL. I didn't do it for bragging rights, to impress anyone or play the "big dick" game. My car is still slow and I still need to work on my drivers mod. It is a very fun car to drive and I don't regret the KL swap at all, but I'm not one who would bash a boosted or turbo'ed FS-DE. Boost is VERY fun. I drove my roommates modded MSM last weekend and the sounds, surge from the turbo are badass.