$1500 for everything is very hard to do. It can be done but most are lucky to purchase cheap head units that are still in good shape. If you're looking for a head unit with low mileage then you won't find one for cheap. If you feel comfortable with buying one with 30-40k miles on it then sure you can probably pick it up for around $600. I bought my V1 S trim with 3.6 pulley, discharge tube, bracket assembly, oil feed/drain assembly, and Vortech air intake used with 4,000 mi for $2,000. Added a used maf and injectors. Bought new svt focus pump, belt, powerpipe with filter, spark plugs, boost gauge, wideband gauge. All this stuff equalled another $950. Then I had a custom aluminim mini catch can made for $60. So $3,000 before install and tune. That is absolutely everything you would need. Of course you don't need to do a powerpipe, catch can, or gauges so if you don't want those items you could save yourself around $525. Also if you buy a used powerpipe and fuel pump you could probably save another $100. If you want to add an itnercooler that will be another $300. I would say you need to budget about $2500 for a decent used setup.