2 inch lift shackle for an MJ will lift you up 2 inches. This, however, means that they're at least 4 inches longer than your stock shackles.
If you're looking to get about 5 inches of lift, your best option is simply doing an SOA conversion. All it'll cost you is a set of spring perches, some welding, and a longer brake hose. If you do it right, you won't even need longer shocks.
On top of that, many people will tell you to stay away from Rusty's. Also, you can't realistically do 5+ inches of lift up front with just spacers. A lift that high up front you need new everything. All 4 control arms(preferably adjustable), track bar(preferably adjustable), shocks, coils, sway bar links, brake hoses, etc etc.
A lift that high is going to be expensive. Lifts, and especially strokers, aren't something you try on a budget. Do it right or don't do it.
Good place to read up in strokers : http://www.jeepstrokers.com/forum/index.php