need help building my first sub

Pierce Audio Products sells softparts to the public. Nice quality too IMO. They may also be able to hook you up with basket.

Look for the rubberized CA glue at hobylinc.com (personally I like to use the spray activator with it). Amazing goop brand glue works well for surround to basket and dustcap to cone (also to reinforce the tripple joint).

For shims I use cards. PPL use index cards, or I've even used strips cut from manila envelopes....use whatever as long as you can get it snug and evenly laid in around the pole piece.

Robot Undergound sells some hard to find parts depending what you need and has some really nice terminals (similar to push terminals but they screw tight...I like them a lot).

Spiders you'll use will depend on the basket. I believe someone around here has a Shocker Neo-Sig motor. Start with that

Unfortunately you really don't know what the sub you build will do until you build it so IMO if you're just going to frankenstein a sub together don't stress too much what kind of suspension, cone, coil, etc. you use. Use enough spiders to handle the power you need to throw at it (unless you're doing extreme burps I'd say 2 is as many as you'd want). Make sure you figure out what the precise specs of your motor are so you can plan a coil that will fit properly.

I've found some great softparts on forums, grab what looks good and have fun with it.