a $30,000 budget will get you a pretty nice restomod, even if you have to farm out a lot of the work. my best advice to you is this;
1: start with the best car you can afford to buy. the better the body, the less expensive the rest of the build is going to be. rust repair is expensive, and really eats into the budget at a rapid rate unless you can do a lot of that type of repair yourself.
2: after finding a good condition body, you want to first concentrate on stiffening up the body and chassis. the reason for this is that everything else is built on this foundation, and if the foundation sucks, the rest of the build is going to suffer badly.
3: when dealing with
suspension, you need to take a systems approach to get what you want. if you just start grabbing parts, you are going to have a poor handling car that also has a poor ride quality. bling parts are nice, but again, just like the chassis, this is the next step on your build as the stance, ride, and handling all come together with this part.
4: when dealing with the drive train, you need to be ABSOLUTELY honest with yourself in what you want from this car. if you want a daily driver, or a back up driver in case the main driver goes down, you want a car that is dependable with a capital D. and if your significant other is going to drive this car, EVER it really needs to be dependable, and drivable. thus a 600hp 393 stroker windsor and 6 speed manual trans is probably not what you want. a nice 347 that makes around 350hp at most and a good automatic, a proper AOD for instance, coupled with say 3.55 rear gears and you have a nice package that will work nicely on the street and be reasonably economical to run, and pretty much dead reliable
5: when you are dealing with external bodywork, stay conservative there. no wild fender flares, or eleanor body kits, etc. if you want a front spoiler and rear wing, thats fine, but again be conservative. and when it comes to paint work, a candy paint job really looks cool, but it costs a lot of money, AND you will be very afraid to park the car anywhere, let alone drive it, for fear that if the paint job gets damaged you will have to seriously consider killing yourself because you are now in for another $10,000 minimum paint job as everything has to come off and totally resprayed. a good solid color, perhaps even a metallic paint job will serve nicely and get plenty of positive comments without breaking the bank.
6: the interior also needs to be comfortable, perhaps with good heat and a/c, and a decent stereo system, remember you are going to be spending a fair amount of time in this car, so comfort is a requirement.
one more bit of advice for you, pick a theme and go with it beginning to end. for instance a road racing looking restomod should be shaved of all its emblems, and as much chrome as possible. it should LOOK the part. if you are going for an updated restored car, then you want all the emblems and chrome, but do NOT go overboard there either. keep it as clean as the factory did. a couple of emblems here and there, and a bit of chrome but no more than the factory. if you are going for a full on show car, you dont have enough budget for that, you need at least triple that $30,000 budget.