you can expect between 25 and 35 bhp increase, they are very relaible if fitted correctly and mapped properly, as for fuel economy you should see a gain if anything! on th motorway i get 40 mpg! obviously when you boot it you use a bit more though
as for price , about 2000 from sbd as a kit form but maybe a little cheaper if you shop around and buy th bits seperately, but sbd would be the easiest option
I've got the taper TBs from SBD on my corsa. Been on for about 4 months now. My engine is not as highly tuned as Region's, but I have still noticed a huge improvement and reliability is great. The fitting isn't too complex, but you need to take your time and research it properly. The only big drawback is the price which is a least 2 grand.