Hi ya
just my pennies worth
"Likely:
Change to a 17% - (would I really notice 2%?)
Performance cam - (no idea what these are like or how good the standard one is)
Water spray for intercooler
Uprated bypass valve
Bigger Injectors (not really sure when theres are needed)"
Right from the above list
15% to 17% would not waist your money, no real gain it will only move your power band and you will start runnining it to other problems heat wise in the summer
1320 cat cams are very good from what i here, but if you don't get your head flowed you will not get the benefit from it, so personally don't waist your money till you have the head done
water spray i would not bother if your standard ic will be running far to hot to make a difference
bypass valve just
mod your own one do the vgs
mod to it, and set the butterfly up properly this will give you the same effect as the detriot tuned one or similar, the bypass valve will only give you more power if its not set up properly otherwise no real advantage
bigger injectors ok but you will need a remap to get full potential from them and with out a good head, cam, inter cooler and exhaust it will be lost
as you start to push more power from you engine you need to change you exhaust manifold you can get one cheep OBX are not to expensive and close copy to the super sprint ones i think
Unlikely:
Uprated intercooler - (having studied the tests I don't think the standard one is at all bad especially coupled with a water spray, not worth the £500+ for GRS/Forge)
Head porting - (too expensive)
Sport Exhaust manifold/cat (I here no real gain over standard)
from above
uprated ic look on ebay get one from a mini GP and do the
mod, the standerd min ones are not very good soon as you start to tune the the car soon as the warmer weather comes when you start to push it any power gains you thought you had will be lost due to high air temps in you inlet track causing you to loose power
again you dont really need water spray (water meth may be but you have a way to go before you can use that
head porting is not to bad depending on what you want seen basic jobs for £500 ish but a good cylinder haed porting job will open up a lot more scope for power
Performance heads | Minispeed for Mini Parts, Servicing and Repairs
exhaust manifold there are gains and will be more noticeable when you have the correct set up
personaly spend your money in the correct places or you will be rebuilding you engine
my advice
buy your self a good cold air intake system this will be better than the panel filter, stick with your 15% pulley, change your spark plugs to NGK BKR7EIX or similar which you should have done all ready when you put the pulley on,
get a GRS or mini gp ic you can keep an eye open in the classifieds here at mini2 of keep an eye open on ebay for a second hand one.
then exhaust manifold, injectors and remap, head and cam and re remap
remap you should go to 1320 mini.
also a thing to take in to consideration is has you car got a LSD you may need one with extra power, as you push the power you will need to think about clutch and flywheel assy
but most important before you start to tune your car make shore all you suspension and brake can handle it
my advise speak to 1320 mini save your hard earned then go see them
hope this help