[MDPotter]

I'll answer as much as I can here without getting too deep in the weeds.

Cam and springs will get you the biggest gain, I would anticipate 50 HP. That engine probably makes 295 in stock form, and even with cold air intake and free flowing exhaust, you'll be short at least 40 without other mods like an LS3 intake or having your heads milled to bump compression.

A lot of guys have been able to adapt the stock behind the seat tank to work by adding a return line and an inline fuel pump and filter. I went with a Tanks Inc universal tank and in-tank pump, but that's $650 and not nearly as convenient as a Boyds tank.

Keep the accessory drive if it came with it, otherwise just scrounge up parts from the junkyard and from Rock Auto.

You'll need motor mounts as well. I used the stock perches, but bought new rubber mounts with aluminum adapter plates.

You might have to buy or fab a transmission crossmember.

A lot of guys make the stock gauges work with the LS too. I spent some money and went with New Vintage gauges, but not necessary.

If it's an 02, it's probably drive by cable. Easy enough to source a cable throttle body from the junkyard and hook it up to your stock pedal.

You can buy PCM's for pretty cheap that have already been programmed to get rid of VATS and other LS-swap required changes. If you're putting on power adders, you'll need a tune though. I don't know how familiar you are with tuning, but you can buy HPTuners and do it yourself for not much more than you would spend on a dyno tune or a mail-order tune.

I spent $200 on a radiator with dual fans and trans cooler on eBay and it works just fine. The fans are cheap so they will probably go out eventually, but no big deal to change them out.

I'm running stock intake and injectors, but they're pretty well maxed out with my moderate cam.

Power steering - I'm using a reman LS pump. I had hoses custom made to connect to the steering gear and booster.

There are plenty of builds on here with LS swaps (mine included), so my advice to you is to start reading through those builds and researching products because there is such a huge aftermarket for LS swaps.

Be prepared to spend some money though. It can nickel and dime you when you start replacing engine parts (spark plugs, wires, water pump, belt, starter, etc.) and there are a lot of little fittings, electrical items, etc. to make it all work together.