[bobcowan]

A few thoughts.

Heat and air. Sounds good on paper, not so good in real life. The first cobra I built had a heater. When I was stopped at a light, the heater felt good on my legs. Otherwise, it seemed kinda useless. I didn't bother putting one in my second car. I suspect A/C would be about the same. Instead of a heater, consider heated seats. Or get an electric vest from the motorcycle shop.

The top is a nice thing to have. When the top is on, you don't get as wet. But, it does leak, and it is drafty. Doesn't look that good, either. But, the new Whitby top is probably the best on the market. Certainly is an improvement over previous iterations.

IRS is the way to go for a cruiser/driver. The differance is night and day. If you're actually going to drive your car on the back roads of the US, you want IRS. You'll spend a little more money, and a lot more time. But it's really worth it. I'v built and driven both. And - unless it's a track car - I wouldn't consider a solid axle for the street.

Rough roads are not that big of a deal. Use 15" wheels and tires, standard issue shocks and springs, IRS, and it will ride just fine. It is an old fashioned sports car, and not a new Caddy. But I think the ride is fine.

Mileage depends on how you build the car, and how you drive the car. Today I went for a drive in the mountains, over 200 miles. Twisty roads uphill in 3rd. Steady cruising in 5th. A little bit of everything. I average 18mpg. Last july I drove to Jackson Hole. Steady cruising across WY got me better than 20mpg. Not bad for well over 500hp.

Keep in mind that anyhing that adds weight, or uses engine power to run, is going to cost you in mileage. That includes power steering.

EFI is the way to go. Even Harley doesn't sell a carb'ed bike anymore. If you want a trouble free driver that gets decent mileage, you need EFI. Lots of options there, some cheaper than others. Just depends on what you want. I'll never go back to a carb.