Thanks to everyone for the responses to my questions ,

Mike did you know later model 13b's have lighter weight rotating assemblies , also
alloy water pump housings . The series 4 is decompressed and the series 5 is high
compression . They both have much higher quality rotor housings , crome/moly
( I think) surfaces instead of the crome plated steel ones in the earlier motors .
The standard port opening and all the after market ports I have seen are not very kind to the
side and apex seals . Observe the area on the side housing just above the port ,
there is always a shiny little nick where the side seal closes . This causes premature
blowby , and can be eliminated with the correct port profile .
With the swiss cheesy looking rotor inners , Check for possible oil supply problems .
some bozoes like to remove the springs and ball bearings from the oil jets in the ecc
shaft .
I cut my teeth on an RX2 as well , 95000 miles worth .When putting headers on any
rotary there should be an increase in both top and bottom end power .
If only the top end increased this would suggest your pipe dia was too large . What type of
port job , header length and dia was your RX2 ?
Will you be running a water temp themostat?
You can plug the water bypass remove the thermo and increase cooling , make sure you
put a wire coil in the bottom radiator hose to avoid the water pump sucking it flat .
Thats one thing less that can go wrong .
Have you seen some of the smaller rotes available through Wankel and Midwest ,
They are around 50kgs with redrive giving 70 horse , offering a choice of fuels even
diesel . That would have to satisfy the fuel misers .
Per horspower the wankel would use very little more fuel than pistons , and according to
Mike Dwyer less at cruise revs .
Yes I have heard of Tracy Crooks EMS's and redrives , by all accounts very good systems .

Seeya Sammy