Hotbits extractor can get from speedworks... last time I used hotbits extractor also... not bad lar the performance... really not bad. Haven't tried powerzone, but theirs is supposed to be the best around... it comes with a price though. I not sure how much are the extractors now, back then hotbits ones going for 300+, powerzone 400+.
Fuel consumption... i not too sure laa... forgot. Hahhaa... mod mod mod, FC like how also didn't bother to care lar... as long as u mod, FC sure slowly become worse and worse wan.
Rechip + cam? No need la... i meant for the mivec only... coz' mivec made for high revs... so if ur engine can't high rev, no point lar. CAn't unlock the full potential of the mivec extractor.. so in order to be able to rev high, have to put cams + rechip lar... anywayz, no point lar... really. Just go for the hotbits or powerzone... 4G91 is not a performance engine... so just concentrate on improving the mid range can already... it'll be a good driving car! =) 4G91 for a 1.5 the power is already not bad wan... =)