I'm considering selling my 99 M3 and getting a newer 335 or 5 series. I was wondering if there is a significant difference between the turbo 6 and V8 engine performance.

 

if you don't need the additional room that the 5 provides, go with the 335. if you need the space, def do the twin turbo v8 550.

 

The Turbo v8 550 is offered after 2011 though right?

 

I didn't know there was a turbo V8. I'm interested in the turbo 6 vs the standard V8 engines. Gas mileage is more important to me than balls-out power...but I still like a car that can get up and go.

 

Only true on F10

 

Bone stock the V8 has about 60hp more than the TTI6. The N54 motor does have some turbo lag but I wouldn't say its annoying. My understanding of the N55 motor is that the turbo lag has been reduced even more - hopefully someone who owns a car with this motor will chime in.

The significant difference comes with aftermarket mods. A basic tune on the TTI6 by itself will match the V8's output power and response. Simple bolt on mods and a more aggressive tune will get about 400hp. Better downpipes, intercooler and a meth injection setup and you are pushing close to 500hp. The V8 can't reach these levels without a power adder.

 

Both car are similar, if we are talking about E60(2004-2010). Only difference the V8 is more smoother, but it doesn't feel that V8 is much faster then 535. Also after driving 535 for couple weeks, I think, the 535 is felt lighter, but not faster. I like Idrive on 535 is much better, then on my 2007 550. Also I like a little storage area at front of gear shifter on 2008+ models. I have ashtray there, absolutely useless thing, now days.
In maintenance wise, the V8 could have a center return cooling pipe is leaking in middle of the engine, this is worst thing of all of it. I did research on this problem, and it seems to me it has to do a lot with 745 and sometimes with 545. The 550 has less accrued problem,I'm be able to find only single incidents. But I6 turbo has carbon build up easy on intake valves, and could have fuel pump and fuel rails fails.

Also if want to add extra 100 hp to V8, then supercharge is available from ess tuning. http://esstuning.com/

 

As pukka mentioned, TTI6 will match power on V8 E60 with a simple tune. In fact, I remember the day I had GIAC flashed, on the way home on the 91 fwy. A nice E60 550 was also flexing, so I engaged. We shortly ran outa room as traffic built up and I managed to out manuvered the 550 by a hair, enough to stay in front several cars. True that the I6 is lighter than v8. So if fuel economy is on your mind, def go with TTI6. When driven normal, you'll be good gas efficiency and when you want WOT, well it kicks a$$.

 

If sticking with the E60, hands down the 535i with the TTI6.

 

4.8L Hauls a$$!!!!