Website displays a very wide range of high end vehicles.They may know something about many, but cannot be specialists in all.
Reviews on website and Internet appear to be very good.
If prices are close to used Lexus Dealer prices, then it is a nonsense to buy from them rather than buy from Lexus.
Boss does not appear to warrants its vehicles,but instead uses a 3rd Party warranty eg, RAC. The small prints in such a warranty will include caveats which are not included in Lexus warranties and should therefore,in my opinion be avoided. Caveat Emptor.