I asked CAA the question yesterday and they were non committal. I have removed the dataplate of the RV's lycoming engine. I call it a a RVcoming engine and I will maintain according the to manufacturers maintenance schedule (I am in process of writing it)
If you "modify" the rattex it no longer a RATTEX and thus is not subject to RATTEX manual? I don't understand the where the EXPERIMENTAL nature of NTCA aviation got lost.
I have a VW on the Cubby and it just been O/H at 700hrs As a result of abuse rather than K@K engine - run without oil
).) Tip to tail plane rebuilt with almost all new components and it cost less than R40K all in. It has been hammered as a flight school aerie and not looked after and has not had any major engine incidents. The rattex version is R40K more new and requires R100K more engine maintenance over same time? That why I did not replace it with Rattex 582.
Surely if you sign a declaration that are using as experimental engine then where is the problem? For school and commercial they "MAY" have a case, but I will not fly a dangerous aerie. I tend not to risk my life for fun, but forcing the AD's and the resultant escalating costs is what resulted in experimental planes in the first place. It going full circle. We will simply be forced to go back to grass roots and use uncertified filters and plugs etc and thus it invalidated the RATTEX warranty and make it an experimental engine? I think there gonna be a huge market for the 300 hr rattex engines...
WHAT AM I MISSING?
I found a RV in Canada, but could not buy it as engine had 2300hrs on it. Guy who is selling it has another with 3600hrs on the same engine unopened. He flies over some of the
country I have ever seen. He maintains if you look after it it will go forever. As soon as you open it it will give you shit. Blow Bye's are all within limits and it hardly uses oil? Locally we are not allowed to run experimental engines (lycoming or Conti) over ecommended TBO. Why then bother with NTCA if it going to be controlled just like TCA?
I still feel that NTCA as a category at CAA is too big and that is the root of the problem....
do I chuck the Rattex and install my old trusty aerovee 
My point is , we are not certified. We do not fly over any build up areas. The term grassroots aviation started with a few guys who wanted to fly and went forth took calculated risks. This is what seperated us from the rest. Now we are being forced into a category with more and more red tape. I seem to remember this happening and most sports. It starts small and as it gains popularity it becomes a rich man`s sport.