My REV1 had smaller brakes and non-bilstein standard suspension which the REV3 versions come with, no abs, no traction, no power steering, no airbag, no strut bars....Made it very fruity when driving in the wet.
You can go on MR2OC.co.uk, the forums always have rev3 bilstein standard suspension for sale, but I bought aftermarket coilovers for about £600 (Tein HA Coilovers) and fitted REV3 calipers all round with Greenstuff discs and pads, but standard ones can also be found cheap on owner's forums or ebay.
Strut bars were about £100 from Cusco (Helped a lot!)
As for colour coding, this depends on bodyshop you go to, but shouldnt be too much as all it is is the bigger front splitter colour coded and side strips.
The rev3 rear lights go for £200-£300 depending on condition, whether they come with the centre panel, looms and locks etc...
To get to 300bhp, you are best following the same rules as any other turbo car - SERVICE IT STRAIGHT AWAY, Sort out breathing with induction kit, uprated intercooler, Exhaust system de-cat and manifold, uprate fueling and boost, get a good ECU and you should see huge gains with the 3S-GTE engines!