variable vale timing is nothing like vtec.... If i rmeember correctly. Vtec has a secondary set of highrevving (different lobes for top end power) cams that switch on by sliding rockers.... no wait sliding a pin threw the rockers if i rmemeber correctly thus utilizing the high rev cam when certain rpms are reached. Variable valve timing with intelligence (VVT-i) does not have a secondary cam set and cannot allow anywhere near the top end power/high revs vtec can. I think im right but not positive. Well almost positive. But also the tvr makes more power because it is tuned to. Nissan makes a 300hp version of the Vg35 as well you jsut lose some torque thats all. The 287hp is a compromise between torque for the street and hp for racing. Obviously there are many other factors like compression, combustion chamber design, head design, etc etc. All these things add up.