I think it's been discussed on here before, and even the idea of putting an RX8 rotary in a car for Proto. But I think the issue with the newer engines was that they were too wide for most Clubmans chassis.

That's not so Andy, I was well down the design route (for feasibility) with a twin rotor Mazda, no problem with space.
There is a problem with the rules though as they specify a 4 pistons up to 2 ltr.
There are issues with silencing them and also how the capacity is derived again in motorsport rules.

Thanks for the clarification.

Pity, it would have been interesting to see.

Here you are Andy http://www.ebay.co.uk/itm/Mazda-RX8-231-Refurbished-13B-MSP-Racing-Beats-Street-Ported-Engine-2-Years-WNTY-/272382128225?hash=item3f6b3d7061:g:MiwAAOSwE6VXJnXq

My hearing hasn't fully recovered from being at the 1991 Le Mans 24 hours......:-)