Blimey Neil, you must be in turmoil. Very difficult I know. Having something unique is special. If you feel that you are not ready then its not the time to let it go or else you wouldn't be feeling this way.
Your car, my car, Jamee's car, Vocky's car and all the rest who have ploughed thousands of pounds in their cars will NEVER see that money back. We do these things for a reason. Its something that we are proud of and love doing. The feeling of the car, the performance, knowing that people are interested in something that you've created.
Stick with it mate.
;-)