For $15,000, you could buy an '87-'93 5.0 Mustang and have it running 10s or lower, with money left over. I really don't know if I'd consider a civic a cost efficient car for making go fast. To get a Civic into 13 range, you gotta do a ton of work (swap, some sort of FI, etc). If you had a DSM, you could spend less than $1000 in parts and be in the 13s (or lower). Mustangs and DSM would be cars I would consider cost effective for making fast, but as a tradeoff, you don't get reliability. If you ask probably 90% of the people on here why they drive a civic, its not because its cost effective to make it fast (b/c its not), but because you can have a 13 seconds civic that you can drive everyday and never have to worry about breaking. Its all about reliablity my friend.