SEQURE M10-25Q FPV GPS Module with QMC5883L Compass Dual Protocol Upgraded 10th Generation Chip Fast Satellite Positioning for FPV Racing Drones

I can give you an exact part list for a 5 inch, because that's what I mainly build. I'm not sure how much you know about building these, but just a quick overview: Minimally, you need a frame, a flight controller, an ESC, motors, a receiver, a battery, and a video transmission system. You can use any mix or match of those provided they fit your frame and meet your requirements for what you want out of it. Frame Frames are almost all the same. They have slight differences in build quality and features, but they are almost always milled carbon-fiber frames. I use this one for my 5 inch:https://www.amazon.com/dp/B082SPT5D9 This is a direct copy of the geprc-mark-4 frame, which is very popular, and easy to find 3d prints and stls for. You can buy any frame you want, though, for any price-point or feature set you want Flight controller & ESC This is often called your "stack", and will very often, but not always, come bundled together. The flight controller is the PCB you will use to solder up all your logic-level connections and stuff to. It is the "brain" of the drone. The ESC takes those low voltage, low current signals from the flight controller, and turns them into 3 phase, very, extremely high current power. Like ~40amps in an instant. We keep all that isolated onto its own board, but thats the job of the ESC. The main thing you care about is the size of the mounting holes. They come in 30x30 and 20x20mm mounting holes typically, where the 30x30 is 5in, and 20x20 is a 3in. The seeker3 uses a HAKRC 7220V2 stack. I'd recommend speedybee's flight controller / esc combo. Depends on your budget, but you get what you pay for. I personally use the SpeedyBee V3 F7 which I paid $119 for. The official v3 f7 has been superseeded by the F405 v4: https://a.co/d/0dycmboT If you want a lower cost option, searching f405 will get you the results you want: https://a.co/d/0gcHFgQD This is a budget knockoff of the f405. If you want to build a 3inch, just add "20x20" or "mini" to the fc stack you choose. Motors Only thing you need to care about with this is the mounting size and the kvs dont exceed your esc or battery. The motor will say which battery is supported. For a 5 inch frame, I use these: https://a.co/d/09hI8JwN You can find any motor you want adjusting for your personal risk tolerance and acceptable pucker factor. The seeker3 uses a 4kv 1505 motor. Check the frame details, it will tell you the mounting holes, but this would be comparable to their motor for a 3 inch frame: https://geprc.com/product/geprc-speedx2-1505-4300kv-motor/ Receiver Need to decide which frequency you want to use, but assuming you're going with the typical 2.4ghz.. The seeker3 I have uses a no-name receiver knockoff. In order to flash the firmware, I had to use the flywoo build profile, but this is 100% not a flywoo chip. I have no idea if that is the standard with the seeker3, but the receiver on it sucks. I was only able to figure out which target I needed in the elrs configurator after failing to apply an update and going to github and finding a matching target from the debug message in a json file. It was running elrs 3, but everything else i have is on elrs4, so updating was necessary and frustrating. I use the Radiomaster RP3 ELRS receiver, which is, in my opinion, the best-bang-for-your-buck receiver on the market. 3in or 5in, doesnt matter, this will work https://www.amazon.com/dp/B0BGBKG635 Battery Not much to say. If you're using a 30x30 fc, good chance you can run a 6s lipo: https://www.amazon.com/dp/B0CGR7TQ44 3 inch, run a 4S: https://www.amazon.com/dp/B0C3J3T5C3?ref=ppx_yo2ov_dt_b_fed_asin_title Video transmission system o4 air pro, or o3 are both excellent quality choices, but there are actually great budget friendly options which are modified dji cameras. Just assuming you want the best on the market: https://store.dji.com/product/dji-o4-air-unit-pro?vid=180741 Optional For a 5 inch, you're going to need a remote id module. sub 250g 3in drones you probably dont need this [?] but I always include them. I personally use the the FT EZ ID: https://store.flitetest.com/ft-ez-id/ And if you want the best-in-class GPS for return-to-home functions with a compass, which will enable autonomous flight, this is probably the best unit for the money IMO: https://www.amazon.com/dp/B0D7Q27CT1?ref=ppx_yo2ov_dt_b_fed_asin_title Totals So in total, something like: Frame: $35 FC/ESC: $84-152 Motors: $63-87 Receiver: $25 Battery: $48 Remote ID (optional): $70 GPS (Optional): $25 Minus the VTX: ~$350-442 Add whatever video system you want: VTX: o4/o4 air pro: $109-$229, significantly cheaper used on ebay All of these are better than what are on the seeker3 in my opinion. They are basically top of the line hobby tier parts. You can slot in any part you want at any point here, all of these items are interchangeable and upgradable. Edit: I forgot propellers. $20 for a bag of them. Edit 2: If you do go this route, go for the mark-5 frame as opposed to the one I linked. You can find cheap knockoffs. If it looks the same, it is the same. That solves a few annoyances with the v4 frame I think are worthwhile. Namely around mounting holes for peripherals making a bit more sense, and changes for the o4 camera, but, of course, more money, coz its newer. Here are the official frames from geprc; https://geprc.com/product-category/frames/5inch-frame-kits/