I've been considering swapping from my CRX to a Civic Hatch for the extra room and the rear-opening hatch. I have a roof-rack and bike-racks that I want to put on the roof of my car, and with the CRX the top-opening hatch hits the bike racks before it gets very open. Also, I wouldn't mind the extra space for occasionally hauling a few more passengers around.

I love the fuel mileage I get with my current setup. How much should I expect that to decrease if I swapped my engine/trans into a Hatch? How about if I used a VTEC-E (D15z?) engine?

 

Why not just swap the trans? What motor do you have in your hatch? You should also use the search there are some great thread on gas sipping swaps.

 

I don't have a hatch yet. If I do swap, I'd be looking for an empty shell in good condition. My brother would like to buy my CRX and get a fresh motor and trans installed in them.

None of the gas-sipping swaps I've seen even come close to the mileage I currently get. All-city driving, without be especially light on the pedal, easily gets 35MPG. Mixed driving is easily in the 40MPG range, and highway driving gets 45-50MPG depending on the season (or more accurately, the temperature).

I've considered putting a fresh VTEC-E into the CRX... but it's not exactly cost effective when I'm already getting phenomenal mileage.