No news that I have seen on a updated mbx5t coming out any time soon. Mugen was released before the xray truck but with xray coming out with the 808 you have to think that they will have a version similar to the buggy coming in truggy.
Xray makes great stuff but they tend to come out with new models frequently. In the last 2 years I believe they have had 3 new buggies come out but Im not positive on that. Other negative on the xray is doesnt it use e clips instead of captured hinge pins.
If you want a 4 shoe clutch you can buy pretty much any clutch and install it on the engine. If you want big bores both jammin and kyosho have them and imsure you can makethem fit. Bottom line is both are a waste of money on the prospec. Mugen makes the BEST shocks I have seen yet out of any company and there is no way I would switch. I have never had one leak,never rebuilt them and never tore a shock bladder. They are quite awesome.