33's are going to put a bit more stress on the driveline, from CV's to clutch, axles & diffs etc, it will affect day to day driving putting your speedo out (will read less than actual road speed = speeding tickets) as well as making low range not as low, so you'll end up working the clutch alot more.
with the shackle lift, don't just copy the length of your mates shackles unless he's running a rodeo as well. when fitting an extend shackle it will change the pinion angle slightly, not so much a problem in the back. but in the case of a hilux or similar with leaf springs front & back extended shackles in the front will affect the castor a bit.
keep in mind when making shackles up generally they will only lift it 1/2 the amount you extend them as the leaf spring is fixed at the other end so that extra length is shared across the length of spring.
so if you make new shackles 2" longer than stock it will only give you 1" of lift at the axle, 4" longer shackles will give you 2".
keep in mind extended shackles are illegal, so don't go painting them flashy colours... stealth black works bes and blue shackles won't flex as well as red.
Edited by atari4x4, 30 November 2011 - 08:17 PM.