GUDE cylinder heads opinion

[xb visitor]

Im looking for anyone whom has experience with these,it seems quite reasonable outlay of money for a 20-30 h.p advertised increase. Like any performance mod ..better off believing it makes 1/2 of what the seller claims. But a 20 h.p increase is pretty hefty for these lil engines..and might just pass a smog inspection in Calif.

Turbo is totally un-drivable for a daily driver @200 miles a day and the cost is a waste of $ at 6-7 thousand bucks..Id buy a used M3 before I ever consider that.
A Supercharger is just too much $ once all the engine management stuff required is added , also could as the turbo could " technically" get my car impounded

Anyways Pros and Cons on the GUDE cylinder heads..dual valvesprings, has that caused any maintenance issues? How do you consider their port work and has it made any "real" VERIFIED performance increases...not just a dyno printout we all know that often its usually engineered for sales. Would prefer some side to side comparisions. Thanks in advance