I have 200 Super Bright LED's and i want to make some lighting for the boot. So i was thinking if there are enough LED's for an average of 13.8 Volts, how many LED's would i need or how would i wire them up.

I was thinking about putting them in parallel but im unsure.

well you need to do a series and parrallel circuit, need more info on the LEDS, like what opperating voltage do they like??? then we can go from there!!!

Well, assuming your super bright LED's run off 3v (i had some super brights ones that did), you will get 4 in series to get you to 12v

Then you can have as many of those series strings as you want (theres a lot of current available in a car batt) with the appropriate resistance so they only get the 12v, not an evil 13.8. To get that you would need to know the current draw of the LED's, the some re-arranging of ohms law and all will be swell.