The panner bar under the front has too much stress on it and is making your front end jerk from side to side real fast which is causing a shake . You need a drop down bracket for the bar that goes from your fram to your axle on your front suspension ( panner bar ) You can use the one for a 3 " lift it wont hurt anything , just make sure you get your front end aligned after you install it . If you have not had your front end aligned after the lift you need too anyways .
The front speakers located in the front doors I believe are 6 inch speakers. The rear speakers are 6 inch X 9 inch speakers.
In the 1997 - 2001 Cherokee the front door speakers are 6.5 inch. However they do not match 6.5 inch aftermarket speakers.
1 and 11/16 inch socket.
The 2001 GMC Sierra has 6 1/2 inch speakers in the front as well as in the rear.
1 11/16 inch socket1 11/16 inch socket
It requires a 1 1/4 inch socket.
1 1/4 inch
According to the 2001 Lincoln Navigator Owner Guide : ( the spark plug gap is .052 inch to . 056 inch ) * confirm with the Vehicle Emissions Control Information ( VECI ) decal in the front of your engine compartment *
3" Dash tweeters 6.5 inch front door speakers 6"9 rear speakers
The axle shaft nut requires a 1 and 11/16 inch socket.
6x9 in the back and 4x6 in the front doors but you can buy an adapter for the front door speakers on eBay to allow you to put larger round 6.25 inch in
4 inch front speakers and 5 inch rear speakers