i just switched to an MSD external coil and dizzy cap... felt a little bit of difference especially with misfiring... car starts up quicker and runs better overall... the only problems i had were wiring it up by myself... i didnt splice the wires good enough and they came apart... after i did it right it hasnt had any problems whatsoever... if your friend is just giving it to you for free then take it... if he wants more than $100 then forget about it... ultimately its up to you though... hope this helps out a little bit bro
-Josh