Contrary to you statement, my engine is not choked by a single throttle-body, the engine was built to use a single 55mm dia throttle-body (although I did experiment with a 60mm dia after-market throttle-body but got more consistent flow rates with the 55mm one), a single Nitrous injector, Custom profile cams and as many albeit modified 'standard' components as possible. Both the alloy inlet manifold and the ABS inlet manifolds were Abrasive Flow Machined to increase flow rate (Alloy: +35% flow, ABS: +25% flow) . Originally I had planned to use the ABS type manifold with the Nitrous injection but found the manifolds were cracking due to reduced wall thicknesses and rapid cooling when liquid nitrous was injected (-150C), so I used the earlier style Alloy manifold sourced from a 1.6 Si, when I had the Nitrous system installed. Whilst after-market throttle-body setups like jenveys, do give impressive power increases, they were not part of the design brief nor in budget. If I wanted maximum power out of the engine, and budget had allowed it, then a set of titan roller bodies may have been included, but the build premise was a street car and occasional standing mile/track-day car, the engine is almost 10 years old with no major rebuilds unlike some of my acquaintance's engines, and I understand Tiger sports cars are getting 280bhp out of ST170 engines on Jenveys, but i doubt they have engine longevity in mind.