hi spydurmonkey68, and welcome to the forums my friend!! i would stay away from the hp-bc for modelling friend, as it comes with a .3mm n/n as standard needle/nozzle combo. this combo is just a little too small for model paints IMO, yes, you can get model paints to fit through the .3mm n/n combo, but its real finicky. i would try and pick between the hp-cs, hp-cr, or the omni 4000. the hp-cs has a .35mm needle/nozzle set up, and is truely a well designed, comfortable airbrush that is EXCELLENT for all of your modelling needs, it cost me $105 at dixie......i will never regret paying the extra money, but some here will nag you to death over an extra $35 bucks.....let em' nag i say!!. i used an Omni 5000 for a while, and it is the same as the omni 4000, except for the size of the color cup, and it was a good all around brush for modelling too, but when i the hp-cs came got here, i fell head over heels for the delightful little piece of quality, and it became my workhorse airbrush!! now, as i've been studying lately, the iwata hp-cr's nozzle and needle is a tad smaller than the Omni 4000's, so you should be able to spray the same, or near the same pattern with the hp-cr($59.95) as you can with an Omni 4000, for about $10 less than the omni 4000($69.95) at dixie. with that said, i don't know if you need a hose, compressor and the whole get up, so it may be tough to fit all of that under a $150 budget. MikeV does have a discount on all badger products.
whatever you choose, i'd stay with a gravity feed brush if i were you. they have a few advantages over a siphon feed model.........as in easier to clean, less wasted paint, spray at lower pressures which translates to less overspray. later.