I've probably paid for 30+ dyno / mapping sessions in my 15 years of modifying my Fiat Coupe 20VT, so I know first hand that the peak power figure from a dyno run has very little bearing on how fast the car feels. Its all about "area under the curve".
My Coupe felt fastest when it was delivering about 400bhp - fairly early spool, followed by a huge mid-range, just tailing off at the top end. I've now gone further still and I've peaked at 488bhp. Its still monstrous in the mid-range, but all the excitement is from 5,000rpm through to 7,500rpm. This means that on the rare occasion when I I get to let it off its leash, its utterly ballistic, but for 98% of the time, its just a laggy turbo-nutter Fiat that struggles to keep up with an enthusiastically driven 320D....
I'd love to get the Westy to 185 - 190bhp, but I'd much rather have a 175bhp car that drives nicely and has great throttle response and calm manners
I'll check some of the basics, but I'm happy to throw a couple of hundred quid at some proper expertise to get everything sorted properly