If your buddy has a budget and wants something at a reasonable price, go with a spacer kit: cornfed, toytech, tuff country, daystar, revtek.
For better performance and a budget of around $600-$800+, go with coilovers: Donohoes, Kings, Sway Aways, Teamwest Sway Aways, Fabtech(basic and performance version), Doestch Tech, Bilstein. DO NOT DEAL WITH A COMPANY CALLED AIM INDUSTRIES INC.(
www.truckn.com). They have a set of adjustable coilovers for around $400 for a tundra. Long story short, the product is pretty much crap and their customer service sucks a$$.
Long travel options: Total Chaos, Camburg
To fit 33's, you'll need at least 2"-2.5" of lift and a backspacing of about 4 5/8". I had 4 5/8" BS with 285-75-16 and it rubbed a tad on the mud flaps and on the frame at full stuff and full turn(in either direction). With a 2WD you can go up to 3.5" of lift but, watch out for the upper ball joints.
Then there's a 3" body lift.