Also, Word

Maybe thats the difference in our points of view. My experience is that the 4.6 is not a maintenance hog. Timing guides, vanos, transmission and cooling system every 100,000 miles or so seems reasonable to me, especially when I am over 115,000 and haven't had any of those failures.

I agree with the availability of parts and lower prices but if the LS is not a maintenance hog why should I care? The mileage increase would be great but that would be offset by the cost of the swap, it will take a long time for a payback. I expect a good share of the mileage is from the transmission gearing anyway. I'm way past 400HP with no problems at all. I have always been a Chevy guy (big block) and an LS in a X5 would draw a crowd at Cars and Coffee but with no DIY instructions or kit I just can't get where you are. I would also have to get past feeling like it was a Ford engine in Chevy.

If I blew my engine and the transmission was near death I would take another look but it would have to make a lot more sense than fixing what I have or replacing it with a B7 Alpine engine or a V10 out of a M5.

I certainly would love to hear about the results of making the swap, especially if the HP is near 700 and it is not breaking stuff on a fairly regular basis. I hope somebody does it soon.

Count your blessings. If the car you purchase was enthusiast owned then obviously you will get more miles out of these SAV's before problems but buying a used 4.6 or 4.8 now is a ticking time bomb with no maintenance records. Just out of curiosity what kind of mods do you have to achieve over 400hp at the wheels? How much do you have into the mods to achieve those goals? The ideal build would be a 4.8is with a blown engine or trans to start off with a chassis that has the wheels, body kit, suspension, interior etc right off the bat. Sell off what drivetrain parts are still good to recoup some $$$ and go from there.

Purchasing any used vehicle with 75,000+ miles is a very bad idea without the history. All vehicles have strengths and weaknesses. One should expect the cost of the repairs will be proportionate to the price when new. And, they should expect as the mileage increases the repairs will significantly increase in cost per repair. Certainly that is not always the case but I think that is a critical consideration before buying any vehicle.

It is very similar to the consideration for depreciation. If one buys a vehicle new there should be no surprise that it will be worth much less when you drive out of the dealer.

I bought my 4.6 new. All the attention and abuse has been by me. With the exception of about a dozen times, nobody has driven it but me. It has only been out of Texas once and that was in the summer.

I added Dinan exhaust, airbox, MAF, Throttle body, engine tune and transmission software shortly after I took delivery. That took it to 369HP and 382TQ at the crank. Later I added a Snow Performance level 3 meth injection, 150 shot of nitrous, electric fan with temp controller and electric cutouts. The benefit of meth varies by application but expectations should be 10-20%. Because of the nitrous the torque side increases more than the horsepower side, with a 5000 lb. X5 that is the key to improving time over a short distance, such as 1/4 mile, and with 4 wheel drive you can put it to the ground. The loss of HP/TQ from the crank to the wheels is a guesstimate and the percent varies. I have found the range to be 20-35%. The cluster seems to be from 25-30% from those that run the dynos and what I consider those qualified to provide input--a very small number of people. You can do the math however you choose.

This opens the door for naysayers to shout that this can't be true because this or that wouldn't take it. I am not going to challenge anyone. I couldn't care less. I will say this, if you haven't done what I have done how do you know what will or won't take it.

As redliner said... that's any car, not just e53's (including 4.6's and 4.8's). Work on any vehicle is expensive when you have to pay someone else to do it... I'm glad I don't have to do that.

I bought mine sight unseen with no records recently trusting the word of dealer salesman... yikes. Would I recommend someone else do that? Hell no! Luckily it has worked out for me so far over the last 6000 miles. I see plenty of E53's on the road with tons of miles on them so they can't be all that much of a ticking time bomb in reality. At the shop we'd see them come in for normal stuff, window regulators, CCV stuff, etc with the M62 variants coming in for timing chains/guides occasionally.

I'm all for the OP's proposed swap, but not because of the negative aspects of owning an m62 powered car... I just think it would be really cool and "brave" of him to go forward with it. :thumbup: We all enjoy our vehicles in different ways... and if his is to have an LSX in it with a lopey cam, I'm all for that.

I think the biggest problem from what you guys see to what I am used to seeing is the cold harsh Michigan weather really takes a toll on anything plastic on these cars. Southern states are so much easier on these cars. One of my closest friends owns a german indy mechanic shop and rarely are there m62 cars that come in there that haven't already had the timing guides replaced or need to have them replaced currently. The first M62 I owned was a 1998 BMW 540i/6 what a powerful fun car that was! I was always impressed with how smooth and effortless they were on the freeway. That motor hopped timing and that was all she wrote. That started the LSX swap idea years ago.

I grew up in Michigan. That was why I thought I should mention my 4.6 has spent it's life in Texas. Michigan winters wore me down so it seems to make sense they could cause some components to fail or need repair sooner. Though, it is my understanding, there is more damage to plastic from hot temperatures than cold. Plastic becomes more brittle as it gets colder but for that to cause damage it would need to be bent or have an unusual pressure directly applied.

Crystalworks makes an excellent point. I have always done my own work. If that were not the case I would never own a pricy vehicle that wasn't covered by an extensive warranty