Well from experience, you gonna have to lose the rear deck speakers, and deffinayely do coil over, and hope that they dont bust the rear glass out when you pancake or three wheel due to the chopped off back window, and if it all works without destroying too much it will get up similar to this. I dont know about the trailing arms on your ride but I extended mine but it didnt have to be done I gained maybe an inch. it is deffinately doable it all depends on how bad you want it, I was told anything over 16'' on my car was impossible, Hmmmmm guess they were wrong, or maybe they just didnt wanna get clowned on so hard, lol
what i was told was, you have to get a slip driveline, you will have to drop your mounts, or for all the lift move your mounts to the frame, you need to do your brake lines, maybe do away with your ebrake, take out speakers, cut rear deck. i never tried it and thats what i picked up from reading posts on LIL.
We have a 86 regal with 18's in the rear. unless ur a circus car you wont get full lock up with the 18's let alone be able to drive. but u will have a nice standing 3 wheel. u dont need to loose ur rear decklid. u just have to build a perch on the back of the rear under beneath where the stock perch. and make a nice strudy structure and mount ur powerball and cylinder. the cylinders will be angled towards the front of the car. just put a nice size coil under there so that the car will sit about stock height or a lil lower
extended brake lines, extended lower trailing arms (you'll have to make new mounts further down the frame) extended upper trailing arms, drop mounts, coil over, loose the rear speakers and the torsion bars, slip yoke with the spring. then have fun getting the pinion angles right so that you can drive locked up and droped. i just did drop mounts with adjustable uppers on my cutty and it is a bitch getting the angle right. however now i can drive fully locked up on 14" strokes. can't drive all the way down though cause of the pinion angle. unless you have a serious hopper that smacks the shit out of the bumper i wouldn't recomend it.