I went from a E53 and will say this. The E70 does have 20" wheels so that will not be the issue. As for the performance, you may be a bit disappointed. The ride and handling is spot on and I would say better.

The speed my be a disapointment. There is no tuning other than exhaust and that will be only so much. Ni personally feel the car runs out of power at the top of the RPM range and though it has a 6 speed, the trans gear selection when you hammer it will down shift to low and there is little power tillmthe trans catches up. Compared to a E53 is you may not feel the same raw power sensation

I do feel the E70 is much more refined and a nicer car. I just ordered the 50 and I personally feel that the 400hp and new trans makes this car excellent

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2012 X5 50i ZAP(2VA, 336, 465), ZTP, ZPP, ZPS(6VC), ZCW, ZRC, 322, 4UB, 4NC, 610
2011 ///M3 Silverstone II
2011 X5 50i(lemon)
-- SOLD --
08 550 Msport
07 X5 4.8I sport
04 545i sport
02 4.4i sport
01 540I M/sport
00 SL500
97 SL500