Found these stats on cars.com that includes "standard" and "available" curb weights, which match your weights and those in 5-series brochure for manual and steptronic transmissions.

08 535i- Standard: 3,660 lbs. Available: 3,703 lbs.

07 550i- Standard: 3,803 lbs. Available: 3,814 lbs. (+143 lbs./ +111 lbs.)

08 550i- Standard: 3,946 lbs. Available: 3,968 lbs. (+286 lbs./ +265 lbs.)


Speaking of options, these are the difference I found in the 08 brochure between the base 550i and base 535i: PDC, 17x7.5 vs. 17x8.0 wheels, leather vs. leatherette, folding mirrors, dimming rear-view mirror, & garage door opener.

 

If you're all about bang-4-the-buck like me, then go with the 535i w/tune. For more piece of mind and a little more prestige (at a price of course), go 550i.

Can't go wrong either way in my opinion.

 

yeah, 200lbs equates to 20hp. so....24 hp difference, and most butt dynos will not notice that. blindfold someone not familiar with a bmw (but knows cars) and put them in both, i 100% guarantee you most people won't notice a difference. i had a 360hp muscle car that i drove to the bmw dealership, test drove all 3, and it was pretty evident to me the only car that had a feeling or more power between the 3 was the 550.

 

lol, so a blind person could feel the difference in a car that is only a 2 tenths of a second faster to 60 (550i vs. 535i), but you couldn't tell a difference between your 530i and a 535i that is a full second faster to 60 and has 80 lb-ft more torque?

 

forget both and go with a 06 M5, almost the same price!

 

Well I drove the 535I today it was just as good as the 550I! I kind of negotiated with the dealer and we agreed on 28k its fully loaded with every possible feature sports pkg and premium has 30k miles does that sound like a good deal? The 550I is 38k with 29k miles

 

Maybe the buy in, but if you factor insurance and maint, then not it's not!

 

HPFP

 

To be fair, make sure you are comparing a 535I equipped with Sport Package and Sport Transmission (without X-Drive) when up against the typically loaded 550I.

 

i take it you don't really know what torque is?

from http://en.wikipedia.org/wiki/Dynometer

horsepower = (torque x rpm) / 5252, so torque = (horsepower x 5252) / rpm

that means horsepower and torque are functions of each other, i.e. the same thing.

and you can tout your 0-60 findings all day, but i'm telling you the average person is not going to notice a 24-hp difference but will likely notice a 40hp difference (the difference between the 550i and 535i, weight considered), and especially the difference from a 530i to a 550i (65hp).

also, the closer you get to 0, the more value half a second has because it's proportion to the cumulative time is much higher. i.e. half a second difference between a 550 and a 535 is more significant than a half a second difference between the 530i and 535i. this is all true regardless of what real-world 0-60 times will get you, not just google results.

anyway, we could argue all day. point is that the 550i is most definitely a faster car unless you want to chip the 535i and that is all assuming you are willing to put up with the HPFP issues. there is absolutely no denying that no matter what numbers you are looking at stock for stock.