For 18K I would suggest an Evo IX GT and have it modified to give 400 BHP. Evo IXs can be be bought for about 16K now and a tuning package consisting of exhaust, filter, uprated fuel pump, boost controller and ECUTEK remap will see 400 BHP and about 385 lbft for a cost £1.5K incl.fitting. Have a look at
www.lancerregister.com, lots of members cars for sale and downloadable buyers guide.