I want to expand on the fuel savings.
If you take the Civic's 32mpg (combined) vs the Civic hybrid 44mpg (combined) and if this car is driven 15,000 a year, the savings is $500.
http://fueleconomy.gov/feg/Find.do?acti ... 0&id=31186" onclick="window.open(this.href);return false;
For a 12MPG increase.
If driving 30,000 miles a year it's a more intresting $1000 savings.
2013 Civic "LX Sedan 5-Spd AT" is $19k, and the hybrid Civic is 24k, so even with driving 30,000 miles per year, it's going to take 5 years to make up that cost.
How much is your motor swap going to cost? How much will it increase your fuel mileage? How many miles a year are you driving? Does the savings add up?