I used to think the RMC and G-Force kits were pretty close, (I was under the impression that G-Force was actually a copy of RMC) but I couldn't be more wrong, they are vastly different beasts...
Having recently made my extractors, the hardest part is the rear cylinders (on my LS1 anyway). The rear-most pipes have to bend down sharply to avoid the footwells.
I have virtually no welding experience and I did them, I just took my time and trial fitted things a few times before tacking them together.... They mightn't look pretty but they'll do the job I hope!
