Without going into all of the details about my experience last year, what Mattc says is absolutely critical, order everything, I mean everything you want up front and then don't dissappoint yourself when the deadline is not met, because it won't happen. Why is this I hear you ask? The guy or girl at BPS can and will only give you an estimate of what they are told at the time and that's generally what a consumer wants to hear in order to make a sale.
Someone also mentioned that they won't contact you, correct, you will need to chase them and I mean in person, forget email and phones.
The most critical thing I believe in my book is when you pick up your rig, go over everything with a fine tooth combe before you leave, agree in writing on anything that's not's satisfactory before you tow it away.
Then, above all, shake the hand of who's been helping you, thank them for being so helpful through the process, then ask for the Managers name. Make a point of calling or dropping a note to that Manager naming the person that helped and I can guarantee you one thing, if you need warranty or help, you will be given priority.
It may sound a little sloppy and brown nosing, but to offer your thanks and 5 minutes of your time can make a world of difference.