Engine upgrades - easy options.

[shithotfast]

OK, so when my spyder went on the road, 350bhp in a car that weighed the same as a bag of chips seemed to be seen as fast! Now it seems that around 1000bhp and twin afterburners in an ultima is the norm! - so to save face, what could I realistically (and cheaply!) do to "up" the BHP on my standard carb zz4 5.7 lump?
EG: Electronic ignition, mapping, fuel injection? NOS?
large mouse in a wheel?
Are there any real easy fixes to get a bit more BHP? Another 10-15% would be fine.

[shithotfast]

Thanks for the advice.... I like the Concorde engine route, but didnt it have TWO engines on it? one seems so tame for my soyder. I have two bungy cords avaliable so I think the pair should do it!.