I did the level with the Daystar 2" Kit. I went with 305/50/20 but their were too small (32"). Gas mileage suffered as well. I'd recommend a 285/55 or 275/60 for a 33" tire. Maybe even a 275/65/20 for a little bigger. There's a thread on here for that size tire.
Have you checked into our leveling kits yet? Not all leveling kits are created the same, our design offsets the strut to provide coil clearance on the upper A-arm during droop travel. We have seen other designs that ignore this so the coil can interfere with the arm.
If your keeping you stock wheels you can go with a 305 which is a 33" and a 2" level...level kits are all the same find one with the best price
305 is the width in mm. I have a 275 and it's a 33"
2006 F150 Lariat SuperCrew 6.5ft bed, 4x4, 5.4L, 3.73LS rear, G-Force True Ram Air Hood, Zone 4" Suspension Lift, ATX Artillery Chrome Rims 18x9, Cooper STT Tek3 325/60R18, Westin Ultimate Bull Bar 3" Chrome, Edge Evolution Power Programmer, Custom Side-exit Exhaust with Dynomax VT muffler, plenty of Chrome and Custom Stainless Steel Accents! My Mod ThreadConfused about Tire Sizes?! How Much Air Pressure Do I Need?