M5james: I'm a pack rat so I'll have to go to therapy to get a smaller trailer and tow less.
My car weighs 2990 w/me in it coming off the track on vapors (that's my story and I'm sticking to it...). Acutally, I have to weigh that to be legal and I have 80 lbs of ballast in the car to make weight (I'm about 170-dripping wet). If I trim down spares (currently 10 extra race wheels and tires, 2 spares for trailer, boxes upon boxes of every spare part imaginable, etc., I think I can make it 6k lbs or less. Trailer is 2370 (including spare trailer wheel and tire) + 2820 for the car = 5190 lbs. Not much spare weight carrying there, but it can be done. I'll just bring the 10 or so gallons of 100 octane with me (70 lbs) and mix at the gas station just before getting to the track (25 fewer gallons to carry), cut spares down significantly and I think it'll be a good start. I'll likely get a lighter generator (I'll need a smaller one just to fit it in the trailer). Dogs may have to go on a diet though...
How much can I put in the X5, weight wise, if I have 600 lbs of tongue weight?
Also, they just came out with a garage height model that I can park in my garage so I'll have no truck payment (0% interest, tyvm), no insurance payment for a truck, and no storage yard payment. Trailer is a bit pricey though.
Convenience at home increases. Convenience at the track decreases. One less vehicle to maintain: priceless
Maybe it isn't smart. I'm interested in feedback from others who have towed w/their X5. There is a guy on the west coast that has a tall 24' trailer that he goes to the track in and has no problems up the Grapevine on the 5, so I should be good. Might have to put a large trans cooler on the X5 and larger radiator if heat becomes a problem...I have towed home in >100 deg F temps before across the Mojave and it isn't pretty in the truck up the Baker grade.