I purchased mine through a Group Buy that was arranged on E60.net from a seller in Hong Kong. The group buy has been over for several months now, however, the seller that I bought from still sells Sprint Boosters on eBay. The link below will take you to a current listing for a BMW Sprint Booster that he has listed for $299. The amazing thing is that I ordered mine on a Sunday and he sent it VIA Hong Kong Express mail and I had it in Los Angeles on Tuesday (2 days later)! As far as dealers in the US............I know Eurorev in Inglewood, California (
http://www.eurorev.com/) had some which they also put up for a group buy on E60.net a couple of weeks ago. I just talked to them yesterday and they had one left which they are now holding for me. I will pick it up in person today or tomorrow. I'm sure they can get more and send it to those of you in the US or Canada who don't feel comfortable ordering it from the guy in Hong Kong. To be honest with you the main reason I am not buying my second one from the same guy is that Eurorev is local to me and I can pick it up in person today. However, if I had to order it and have it shipped I would go with the eBay guy in Hong Kong again instead of trying to order it from a US seller. I would probably get it faster from him then someone shipping from the US
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As far as installation..........the Sprint Booster is basically a short extension cord with a small box/connecor at one end and another connector at the other end that you plug in-line with the wiring harness that is attached to the accelerator pedal. All you need to do is unscrew one screw at the base of the pedal and lift the pedal upwards (the screw has a black plastic cap on top of it that you need to pry out with a small screwdriver). You also need an allen key to unscrew the screw (can't remember the size). Then you unplug the harness from the accelerator pedal and plug in the Sprint Booster inline (one end to the accelerator pedal and the other end to the car's wiring harness). All you need to do at this point is install the pedal back in it's place. On my 545 I had just tucked the SB behind the pedal, but on the E70 that didn't seem to work so I slit the carpeting that is hidden behind the pedal and slipped the SB under the carpeting....this allowed for a better fit and the pedal slipped into position much easier. I will use this method when I install a new SB on the 545.
The only things to watch for during installation are the following:
1. Make sure the car's ignition is completely OFF when you do the install.
2. Make sure all the pins are straight and that the connectors line up correctly before inserting them into each other as the pins can be bent if the connectors are inserted at an angle.
Some people that installed the SB on the E60 didn't line up the connectors correctly or had the ignition on and ended up with error messages (which went away after they straightened the pins and re-installed the SB).
By the way, there are two different SB models for BMW's....one for automatic transmissions and one for manuals. There are no manual E70's, so make sure the model number ends with an "A" for "Automatic".
Here's the link to the eBay seller in Hong Kong that I bought my first SB from:
http://cgi.ebay.com/ebaymotors/Sprin...mZ300199162721