np242 specific lift questions

II'm in the process of building up my daily driver '94 2 door XJ for light to moderate off road use and have a few questions that I'd greatly appreciate answers to. Here are my detailed specs.
4.0
AW4
NP242
open Dana 35 rear
K&N drop in
Dynomax Super Turbo cat back
M.O.R.E bomb proof motor mounts
14" electric fan conversion and high output aux electric fan on a Flexalite temp switch w/manual kill switch
3 core rad
TJ flares
Rusty's 3" AAL lift (just installed the rear this week I'll do the front as soon as I have time)
Rusty's tow hook brackets (will install when I install the front bumper)
30x9.5r15 Liberator AT tires (BFGs made for Walmart, 31s as soon as I can afford them)
Rock Rats trail rails rocker protection
Mopar gas tank skid (will install when I install the rear bumper)
custom front bumper w/grill guard, receiver, and D rings (waiting on delivery)
custom rear bumper w/swing out tire carrier, receiver, and D rings (waiting on delivery)

Now for my questions
Is the 242 more prone to vibes than the 231? (I've heard both ways and am confused)
At what lift height does a pre '97 XJ with the np242 usually get vibes?
If it is at 3"-3.5" would the fact that my M.O.R.E. motor mounts raised my engine ½"- ¾" help the situation? (I've read that raising the engine does the same for driveline angles as dropping the xfer case)
If that is so and I still get vibes will I have a good chance of shimming them away?
If so would getting .75" extended or MJ shackles be better than shimming?
thanks

I've never had any vibration issues w/ my ~3" lift and 242

Check with JohnnysXJ - he's got a newer XJ w/a 242

3inches 242 no vibes 90xj

90 w/242 and RE 3.5" lift and I have vibes. Net lift is more like 4.5 inches.
T-Case lower didn't get rid of all the vibes, so I have a SYE and new shaft waiting to go in next week.

When I had my '97 at 3" I had some very minor vibes but in a year I had to replace my pinion gear bearing. What you need to do is get an angle finder and make sure your t-case and pinion yoke angles are parallel to each other. The axle can be shimmed, but I got MJ shackles and I think that is a better way to go, especially if your angles are dead on with the shackles alone.
BTW the 242 ends up with more vibes because it is longer and allows for less driveshaft length and therefore greater driveline angles. The same goes for the chrysler 8.25 as opposed to the D 35. I had both.
HTH,
mattk

i have an 89 with a RE 4.5" lift and no vibes