Would the result be so bad that it's just a waste of money?
Potentially useless comments, but something I wish someone else told me directly when I started down this path:
- remember that there is very often a tendency for people to self-validate. Meaning, to distort the magnitude of the benefit of an expensive purchase. It's common with any sort of 'high cost' purchase, so remember you are reading words that might not be telling the real/true story in line with your assumptions. It's a very subjective topic (my opinion). I find this whole topic very similar to the debate with guitars/amps and the elusive 'tone' quest.....
- I think you need to decide if you're looking to add tactile for some fun (revs, gear change, etc), or for additional feedback (ie. tire slip, grip, wheel lock, etc). Personally, I fall into the 'fun' side, and so what I look for might be different than you/others. The more you are looking to get out of it, the more it will cost. Or alternatively, don't assume a BK kit will allow you access to everything tactile has to offer (which for me again, is highly subjective, and debatable)
- I am convinced there are massive diminishing returns here. I wonder if the money that some are spending on tactile, would be better balanced with other things non-tactile, but still sim-racing oriented (things like VR, better pedals, a good rig, a nice monitor, button box, etc, etc, etc, etc..... the list goes on. I think that there can be far greater incremental benefit to a lot of other things, rather than the 'deep well' of the tactile world)
- I'm not one of the so-called 'tactile elite'... but I've played around enough to come to the conclusion that the absolute biggest benefit is from having 'something', but not getting your expectations too high. A basic BK kit (compared to nothing) is definitely a fun addition, but don't have unrealistic expectations, and use only one or two effects at a time.
- The BK Kit is not likely going to give you a good 'thump' for things like gear change. But it can/will be there, assuming it's mounted in a spot that translates nicely to your body. It is possible to amplify the effect by how it's mounted, and using some leverage to increase the effect. The more stuff between you and the BK (mounts, connections, seat padding, etc), the more the effect is reduced. This is where some isolation helps to contain the vibration to the area wanted.
- the advantage of a BK kit, from my perspective is that you can at least try/understand what lies ahead, without massive investment. Then, if you go further, you can always keep using it together with other purchases. Or, if not, I'm sure those kits are sellable online pretty easily. And, considering this, if you are very undecided to spend a bunch of money..... have a look on your local buy/sell sites..... you might be able to find a used kit for much less, to test your interest.
Personally, I started with 2x BK Minis and the NX1000D amp. But I found that the related kick was not what I hoped for (I was a bit disappointed actually, thinking I was doing something wrong..... but the answer I got was "you had unrealistic expectations and should have done better research"....and that was correct) So I went up from there (but still use the same amp and BK together with other items). But even with some investment now, I still target the 'fun' side of things. And I love to use it with other games and Spotify just running in get background as well. And I do admit, I still remain a bit intrigued by the whole thing. I often watch my local buy/sell for different things and even purchase pieces at good prices over time, not knowing if I will ever use them.
Good luck.