my opinions:
basic tuning>
exhaust and inlet
* you want a 1 3/4'' exhaust for N/A any bigger wont be any gain Lcb extractor for top end 3 into 1 extractors for torque , although difference is minimal.
*throw your std 1 1/4'' su in the shed and replace with somtheing bigger, Im a fan a single su's especially the newer style hif carbs. 1 3/4'' hif44 is perfect for a 1098 aslong as it is setup right, but a single hs4 1 1/2'' su will be more than capable.
add a pulsar dissy and small cam and you will be looking at 40+ hp @ the wheels
my engine is basically that atm and made 43.1hp and gets around 340km to a tank of fuel.
the next option would deffinatly be the head and cam , A Re-13 cam grind would be the way to go id say as all of the top hp 1098's run them.
Head: there are a few optiond here , std is a 12g202 pretty good heads and can be made very good. A cooper head can be fitted but will have to have a lot skimmed off to raise the compression to something decent, unless you fit raise crowned and flat top pistons. A 1275 head can also be fitted but the block will need pocketing or (but im not sure) if hilman imp pistons are fitted you dont have to??? not sure tho
i think thats all for my basic tuning guide , dont quote me it may be worng
