Porting technically from an insurance stand point is "modifying the car" , however I believe there is a line in there somewhere "parts replaced for upkeep and maintenance of the vehicle with oem or alike" are allowed with porting your not really changing parts they are oem just "refurbished" , in the end I wouldn't say the insurance can do anything , sure even the tyres on the car are aftermarket .... theres many views upon insurance and I'm not going to open that kettle of fish but , realistically no there should be no issues from an insurance stand point and even then , they more then likely will never open that engine ... let alone even know what the hell there looking at ...
The key benefits to a street port is as follows:
Information source : @RichieDC
"Corners" are taken off the ports and blended to create a smooth transition to the plate from the port , this will decrease side seal wear.
More power @RichieDC car made 203-204 on the dyno , this car had full exhaust system mani + backbox + decat standard pipe it had d585s and @littlefeck Map on it , More air in + More air out , and some minor timing changes creates more power it seems
Fuel economy seems to get better with the port as a little bit of overlap begins with the porting 2 - 3 degrees if even , I don't know if its @RichieDC and his puny right foot and granny like shifting that is playing a role In that , but it seems to help anyway ! Richie can and does get the 400 mark and beyond ! with some 500's in there ! "cite this as needs be Richie ! "
Smoother intake flow and smoother intake tract
Port Matching always helps to stop disrupt the flow of air !
Power from 4500 till 9200 (once again Richie feel free to correct me !)
The key benefits to a half bridge is as follows :
Information Source : Me @Bradyy
All of above bar 3 ! (See Cons)
Even more air in and the port timing changes rapidly with some overlap of about 10-15 degrees "marginal I know but still"
Bigger exhaust ports , when I ported mine with the help of @RichieDC we went a "bit" bigger to the point of us wondering was this going to work ... it did and creates even more overlap which is about +5 degrees
More Power My car made 202 on the dyno and had everything standard on it apart from a decat standard pipe , we believe it would make more with a map and exhaust system ! best case 220 worst 210 ,
Power from about 4000 till 9200
Half Bridge CONS :
IT EATS BLOODY FUEL ! , if you go anywhere above the 4000rpm mark mpg drops to about 12mpg , above 6500 it drops to about 7mpg ... around town I see about 17mpg and motorway about 24mpg if I drive like @RichieDC
Bottom line really street Porting helps in a number of areas and I would recommend it to anyone that is getting there engines rebuild if not for power and if not for fuel economy simple to take the edge of them bloody sharp ports !