I have a LQ4 and a 4L80 behind it. The Flex plate has broken and I was wondering if anyone else has done replaced one and reused the spacer and all the bolts because I found a plate I would like to use. https://www.jegs.com/i/JEGS/555/601080/10002/-1 . https://www.jegs.com/i/JEGS/555/601062/10002/-1 These are the two I am looking at

 

first i would try and find out if possible why the flex plate broke. could be just high mileage or just the age of the part. high horse power applications usually benefit from a billet flex plate. in extreme conditions the flex plate can break because of a mis aligned transmission, the snout of the torque is worn/damaged or worse yet the back of the crankshaft is damaged. i did not look at your links but if you're going with a flex plate from jegs i would talk to them and see what they suggest. as for a factory flex plate any spacer or washer that was removed should be reinstalled. bolts can be reused just as long they are not torque to yield type of bolt. i always use blue locktite and follow manufacture torque specs.