Retrovalve and ULT?

[spyderkiller]

I recall reading somewhere that the ULT kit doesn't work with the retrovalve? What's the deal with this? I also saw that the retrovalve can be modified somehow (professionaly) to allow for the ULT. I'd like to know how this can be done, so that I don't have to spend $200 on a new X valve to get the ULT. Thanks.

[danheneise]

the easiest way to tell is too look at the top of your on/off assembly, if there are two o-rings on the top, then you should be set for the ULT, if there is only the white teflon o-ring, then you will need to get your valve drilled out to use the ULT

[spyderkiller]

Will any certified airsmith with mag experience(or anyone else with a lot of experience for that matter) be able to drill the retro for a ULT to fit?