I used the "little ripper" set up & it was great.
If the Bluetooth or wireless option is mainly what your after a much cheaper & better alternative is to use Bluetooth low latency rx/tx units like the Avantree Saturn Pro
http://www.avantree.com/product-bluetooth-transmitter-and-receiver-avantree-saturn-pro.html They are more versatile to a variety of uses. You can get a pair of them for as low as $70-90 on eBay sometimes.
Using these I would firstly try them without a booster if using headphones. You should be able to adjust volume enough for headphone use. If you find that you are still wanting a booster then a number can be purchased that will work with the units i.e. LH-380 mini guitar amp, B&Z booster, Vktek Treasuremate II etc. I've used them all & they all work fine. The Avantree units have no noticeable lag at all.
The only issue with the 5000 would still be the battery i.e. you would still be wired from harness to the detector or you can get a control box cover with a battery pouch but I found the Minelab batteries can get heavy after awhile. It doesn't bother a lot of people though. The small camcorder type batteries might be an option there also if you want to be completely wire free on the 5k. Wouldn't be an issue on your CTX.
Edit: p.s. I tried a couple of times to get some feedback on the EQ spirit but never found out much about them being used out in the field. I had one bloke say he was happy with the set up, no probs & another told me he was not happy with the audio performance at all & returned it for a refund. 50/50